Baitap ktlt code

Bài 39
+ Câu a:
#include <iostream.h>
#include <stdlib.h>
const max=30;
//Nhập mảng ngẫu nhiên
void input(int a[], int &n)
{ cout<<"nNhap so phan tu:"; cin>>n; randomize();
for(int i=0;i<n;i++) a[i]=random(20);
}
//Xuất mảng
void output(int a[], int n)
{
for(int i=0;i<n;i++) cout<<a[i]<<",";
}
//dieu chinh day a[i],a[i+1],...,a[n] thanh heap, biet rang a[i+1],..,a[n] da la heap
void adjust(int a[], int i, int n)
{ int x=a[i];
int j=2*i,done=0;
while(j<=n&&!done)
{
if(j<n&&a[j+1]>a[j]) j=j+1;
if(a[j]>x) {a[i]=a[j];i=j;j=2*i;}
else done=1;
}
a[i]=x;
}
void heapsort(int a[], int n)
{
for(int i=n/2;i>=1;i--) adjust(a,i,n);
for(int j=n;j>=2;j--)
{ int x=a[1]; a[1]=a[j]; a[j]=x;
adjust(a,1,j-1);
}
}

void main()
{ int a[max],n;
input(a,n);
cout<<"nDay truoc khi sx:"; output(a,n);
heapsort(a,n);
cout<<"nDay sau khi sx:"; output(a,n);
}
+ Câu b:
#include <stdlib.h>
#include <conio.h>
const max=50;
{ cout<<endl<<"Nhap so phan tu:"; cin>>n;
randomize();
for(int i=1;i<=n;i++) a[i]=random(max);
}
{
for(int i=1;i<=n;i++) cout<<a[i]<<" ";
}
int sub_max(int a[], int n, int j)
{ int k=0;
if(j<=n)
{ k=j;
if (j+1<=n&&a[j+1]>a[k]) k=j+1;
if (j+2<=n&&a[j+2]>a[k]) k=j+2;
}
return k;
}
void Adjust(int a[], int i, int n)
{ int x=a[i];
while(1)
{ int k=sub_max(a,n,3*i-1);
if(k==0||a[k]<x) break;
a[i]=a[k]; i=k;

}
a[i]=x;
}
void HeapSort(int a[], int n)
{ for(int i=(n+1)/3; i>=1; i--) Adjust(a,i,n);
{ int x=a[1]; a[1]=a[j]; a[j]=x;
Adjust(a,1,j-1);
}
}
void main()
{ int a[max],n;
input(a,n);
cout<<endl<<"Day truoc khi sap:"<<endl;
output(a, n);
HeapSort(a,n);
cout<<endl<<"Day sau khi sap:"<<endl;
output(a, n);
}
Bài 2: Cho file văn bản chứa dãy số nguyên, dùng thuật toán merge sort để sắp xếp
dãy số trên file.
//tron tu nhien ba bang hai giai doan tren file
#include <stdio.h>
#include <stdlib.h>
//tao file chua n so nguyen ngau nhien tu 0 den 19
void WriteFile(char *filename, int n)
{
FILE *f; int i;
f=fopen(filename,"w");
randomize();
for (i=1;i<=n;i++)
fprintf(f,"%d ",random(20));
fclose(f);
}
//doc file chua cac so nguyen hien ra man hinh
void ReadFile(char *filename)

{
FILE *f; int x;
f=fopen(filename,"r");
printf("n");
while (fscanf(f,"%d",&x)!=EOF)
printf("%d ",x);
fclose(f);
}
//doc mot so tu file f1 ghi vao file f2,
//neu f1 da o cuoi file hoac so tiep theo nho hon so moi doc
//thi doan con trong file f1 da het, gan endsub=1
void CopyRecord(FILE *f1,FILE *f2, int &endsub)
{
int n,m; long p1,p2;
endsub=0;
if (fscanf(f1,"%d",&n)!=EOF)
{
fprintf(f2,"%d ",n);
fgetpos(f1,&p1);
if (fscanf(f1,"%d",&m)==EOF) endsub=1;
else
{
if (m<n) endsub=1;
fsetpos(f1,&p1);
}
}
else endsub=1;
}
//chep mot doan con tu f1 vao f2
void CopySub(FILE *f1,FILE *f2)
{
int endsub=0;
while (!endsub)
CopyRecord(f1,f2,endsub);
}
//tach filename thanh filename1 va filename2

void Split(char *filename, char *filename1, char *filename2)
{
int flag,n,n1; FILE *f,*f1,*f2;
f=fopen(filename,"r");f1=fopen(filename1,"w");f2=fopen(filename2,"w");
flag=1;
while (!feof(f))
{
if (flag) CopySub(f,f1);
else CopySub(f,f2);
flag=1-flag;
}
fclose(f);fclose(f1);fclose(f2);
}
//tra ve so nguyen ma con tro f dang tro toi
//neu con tro o cuoi file thi gan endsub=1
int CurRecord(FILE *f, int &endsub)
{
int n; long p;
endsub=0;
fgetpos(f,&p);
if (fscanf(f,"%d",&n)==EOF) endsub=1;
else fsetpos(f,&p);
return n;
}
//tron filename1 va filename2, ghi vao filename
int Merge(char *filename1, char *filename2, char *filename)
{
FILE *f, *f1, *f2;
int numsub,endsub1,endsub2,n1,n2;
f1=fopen(filename1,"r");f2=fopen(filename2,"r");f=fopen(filename,"w");
numsub=0;
while (!feof(f1)||!feof(f2))
{
endsub1=endsub2=0;
do
{

n1=CurRecord(f1,endsub1);
if (!endsub1&&!endsub2)
{
if (n1<n2) CopyRecord(f1,f,endsub1);
else CopyRecord(f2,f,endsub2);
}
}while(!endsub1 && !endsub2);
if (!endsub1) CopySub(f1,f);
else if (!endsub2) CopySub(f2,f);
numsub++;
}
while (!feof(f1))
{
CopySub(f1,f);
numsub++;
}
while (!feof(f2))
{
CopySub(f2,f);
numsub++;
}
return numsub;
}
void MergeSort(char *filename)
{
char *filename1="d:temp1.txt", *filename2="d:temp2.txt";
int numsub;
do
{
Split(filename,filename1,filename2);
numsub=Merge(filename1,filename2,filename);
}while(numsub>1);
}
void main()

{
char *filename="d:test.txt";
char *filename1="d:temp1.txt";
int n;
printf("nNhap so phan tu cua day so:");
scanf("%d",&n);
WriteFile(filename,n);
ReadFile(filename);
MergeSort(filename);
ReadFile(filename);
}
bai 6 trang 103
vd pt 2x1+3x2+3x3=5 (n=3,b=5, a1=2, a2=a3=3)
se co hai nghiem la: x=(1,0,1) va x=(1,1,0)
#include <stdio.h>
#include <conio.h>
int x[100],a[100],n,b,count,s;
void init()
{
printf("n="); scanf("%d",&n);
for (int i=0;i<n;i++)
{
printf("a%d=",i+1); scanf("%d",&a[i]);
}
printf("b="); scanf("%d",&b);
count=0; s=0;
}
void result()
{
count++;
printf("n%3d) ",count);
for (int i=0;i<n;i++) printf("%2d",x[i]);
}
void Try(int i)
{
for (int j=0; j<=1; j++)

{
if (s<=b) //dk de chap nhan x[i]=j la a[1]*x[1]+...+a[i-1]*x[i-1]<=b
{
x[i]=j; //xac dinh x[i]
s=s+a[i]*x[i]; //cap nhat bien trang thai s
if (i==n-1)
{
if (s==b) result();
}
else Try(i+1);
s=s-a[i]*x[i];//tra lai gia tri cu cua bien trang thai s
}
}
}
void main()
{
clrscr();
init();
Try(0);
getch();
}
bai 7 trang 103
vd pt: x1+2x2+3x3=20 (n=3,b=20, a1=1,a2=2,a3=3)
se co 44 nghiem la: x=(0,1,6),.., x=(2,2,4),...,x=(20,0,0)
#include <stdio.h>
#include <conio.h>
void init()
{
{
printf("a%d=",i+1);
scanf("%d",&a[i]);
}
count=0; s=0;
}

void result()
{
count++;
}
void Try(int i)
{
for (int j=0; j<=b/a[i]; j++)//cac gia tri x[i] co the nhan
{
{
if (i==n-1)
{
if (s==b) result();
}
else Try(i+1);
}
}
}
void main()
{
clrscr();
init();
Try(0);
getch();
}
bai 9 trang 104
vd: N=5, tach N thanh 1 so, 2 so, 3 so, 4 so, 5 so
5, 1+4, 2+3, 1+1+3, 1+2+2, 1+1+1+2, 1+1+1+1+1
#include <stdio.h>
#include <conio.h>
int x[100],N,count,s,k,n;
void init()

{
printf("N="); scanf("%d",&N);
count=0; s=0; k=1; n=0;
}
void result()
{
count++;
}
void Try(int i)
{
for (int j=k; j<=N; j++)//cac kha nang cua x[i]
{
if (s<N)
{
s=s+x[i]; k=j; n++; //cap nhat bien trang thai s,k,n
if (s==N) result();
else if (s<N) Try(i+1);
s=s-x[i]; n--; //tra lai gia tri cu cua bien trang thai s
}
}
}
void main()
{
clrscr();
init();
Try(0);
getch();
}
bai 10 trang 104: hinh vuong than bi
Y tuong: (moi ma phuong la mot hoan vi)
- tim tat ca cac hoan vi cua tap {1,...,n*n}
- Kiem tra hoan vi nao la ma phuong thi in hoan vi do
#include <stdio.h>
#include <conio.h>

int x[100], b[100],n,count;
int a[10][10];
void init()
{
printf("n=");
scanf("%d",&n);
for (int i=0; i<n*n; i++) b[i]=1; //i chua su dung
count=0;
}
int test() //kiem tra hoan vi co la ma phuong
{
int i, j, k, s, s0, s1, s2;
//doi hoan vi thanh ma tran de de kiem tra t/c ma phuong
i=0; j=0;
for (k=0;k<n*n;k++)
{
a[i][j]=x[k]; j++;
if (j==n) {i++; j=0;}
}
//kiem tra tong moi dong phai bang nhau
s0=0;//gia tri dong 0
for (j=0;j<n;j++)
s0=s0+a[0][j];
for (i=1;i<n;i++)
{
s=0;//gia tri dong i
for (j=0;j<n;j++)
s=s+a[i][j];
//neu dong i khac dong 0 thi khong phai ma phuong
if (s!=s0) return 0;
}
//kiem tra cot
s0=0;//gia tri cot 0
for (i=0;i<n;i++)
s0=s0+a[i][0];
for (j=1;j<n;j++)

{
s=0;//gia tri cot j
for (i=0;i<n;i++)
s=s+a[i][j];
//neu cot j khac cot 0 thi khong phai ma phuong
}
//kiem tra duong cheo
s1=0,s2=0;
for (i=0;i<n;i++)
{
s1=s1+a[i][i];
s2=s2+a[i][n-1-i];
}
if (s1!=s2) return 0;
return 1; //hoan vi la ma phuong
}
void result()
{
if (test())
{
count++;
printf("nMa phuong %d:n",count);
{
for (int j=0;j<n;j++)
printf("%3d",a[i][j]);
printf("n");
}
}
}
void Try(int i)
{
for (int j=0; j<n*n; j++)
{

if (b[j])
{
x[i]=j+1; b[j]=0;//j su dung roi
if (i==n*n-1) result();
else Try(i+1);
b[j]=1; //tra lai trang thai cu, j chua su dung
}
}
}
void main()
{
clrscr();
init();
Try(0);
getch();
}
Giải:
Bài 2:
Hướng dẫn:
a) Duyệt từ đầu đến cuối văn bản chương trình và sử dụng các phép biến đổi tương đương
sau:
+ Nếu gặp lệnh while thì giữ nguyên.
+ Nếu gặp lệnh do..while chuyển sang while như sau:
do
{
khoi_lenh; //gồm một hoặc nhiều
lệnh
}while(bieu_thuc_đieu_kien);
khoi_lenh;
while(bieu_thuc_đieu_kien)
{
khoi_lenh;
}
+ Nếu gặp lệnh for chuyển sang while như sau:
for(bieu_thuc_1;bieu_thuc_dieu_kien;
bieu_thuc_2)
{
khoi_lenh;
}
bieu_thuc_1;
while(bieu_thuc_dieu_kien)
{
khoi_lenh;
bieu_thuc_2;
}
+ Nếu gặp lệnh if chuyển sang while như sau:

if (bieu_thuc_dieu_kien)
{
khoi_lenh;
}
while(bieu_thuc_dieu_kien )
{
khoi_lenh; break;
}
+ Nếu gặp lệnh if..else chuyển sang while như sau:
if (bieu_thuc_dieu_kien)
khoi_lenh_1;
else
khoi_lenh_2;
int flag=1;
while(bieu_thuc_dieu_kien )
{ khoi_lenh_1; flag=0; break;
}
while(flag)
{ khoi_lenh_2; break;
}
+ Nếu gặp lệnh switch() chuyển sang lệnh if else, sau đó từ if else chuyển sang while:
switch(bieu_thuc)
{
case gia_tri_1: khoi_lenh_1; break;
case gia_tri_2: khoi_lenh_2; break;
[. . . ]
case gia_tri_n: khoi_lenh_n; break;
[default: khoi_lenh_n+1; ]
}
if (bieu_thuc==gia_tri_1) khoi_lenh_1;
else
if (bieu_thuc==gia_tri_2) khoi_lenh_2;
else
[…]
if (bieu_thuc==gia_tri_n) khoi_lenh_n;
[else khoi_lenh_n+1;]
Bài 3:
Hướng dẫn
Cách 1:
#include <stdio.h>
#include <conio.h>
#define MAX 100//so vat toi da
int n;//so vat thuc su
int B;//suc chua cai tui
int A[MAX];//mang chua trong luong cua cac vat: a1,...,an

int C[MAX];//mang chua gia tri cua cac vat: c1,...,cn
//mot phuong an la mot day nhi phan x1,...,xn (xi=0/1)
int X[MAX];//mang chua phuong an hien tai
//phuong an toi uu la phuong an cho gia tri lon nhat
int XOPT[MAX];//mang chua phuong an toi uu: xopt[i]=0/1
//gia tri toi uu la gia tri su dung ung voi phuong an toi uu
int FOPT;//mang chua gia tri toi uu
int stop=0;//stop=1 la ngung sinh day nhi phan ke tiep
char *filename="d:data.in";
void DocFile()
{
FILE *fp = fopen(filename,"r");//mo file du lieu de doc
fscanf(fp, "%d%d", &n,&B);//doc so vat n va suc chua cai tui B
printf("n So vat:%d",n);
printf("n suc chua cai tui:%d",B);
printf("n gia tri cua moi vat:");
for(int i=1; i<=n; i++) //doc gia tri cua moi vat c1,...,cn
{
fscanf(fp,"%d",&C[i]);
printf("%4d",C[i]);
}
printf("n trong luong cua moi vat:");
for(i=1; i<=n; i++)//doc trong luong moi vat: a1,...,an
{
fscanf(fp,"%d",&A[i]);
printf("%4d",A[i]);
}
fclose(fp);
}
void KhoiTao()
{
FOPT = -32000; //gan gia tri toi uu ban dau
//gan phuong an hien tai ban dau: x1=x2=...=xn=0
//va phuong an toi uu ban dau: xopt[1]=xopt[2]=...=xopt[n]=0
for(int i=1; i<=n; i++)
{

X[i]=0;
XOPT[i]=0;
}
}
void DayNhiPhanKe()//tim day nhi phan ke tiep
{
int i=n;
while(i>0 && X[i]==1) {X[i]=0;i--;}
if( i==0) stop=1;
else X[i]=1;
}
void CapNhatPATU()//cap nhat phuong an toi uu
{ //X1,...,Xn la day nhi phan ung voi phuong an hien tai
//S la tong trong luong cac vat ung voi phuong an hien tai
//P la tong gia tri cac vat ung voi phuong an hien tai
int S=0, P=0;
for( int i=1; i<=n ; i++)//tinh S va P
{
S = S + A[i] * X[i];
P = P + C[i] * X[i];
}
//Neu phuong an hien tai co tong trong luong cac vat<= suc chua cai tui
//va tong gia tri cac vat > phuong an toi uu tam thoi thi cap nhat
if ( S<=B && FOPT < P)
{
FOPT = P; // Cap nhat gia tri toi uu moi
for(i=1; i<=n; i++) // Cap nhat phuong an toi uu moi
XOPT[i] = X[i];
}
}
void GhiFile()
{ // Dua ra ket qua toi uu
FILE* fp = fopen("ketqua.out","w");//mo file ketqua de ghi
fprintf(fp,"%dn",FOPT);//ghi gia tri toi uu vao file
printf("n Gia tri toi uu :%d", FOPT);
printf("n Phuong an toi uu:");

for(int i=1; i<=n; i++)//ghi phuong an toi uu vao file
{
printf("%3d",XOPT[i]);
fprintf(fp,"%3d",XOPT[i]);
}
fclose(fp);
}
void main()
{
DocFile(); KhoiTao();
while(stop==0)//lan luot xet tat ca cac day nhi phan ung voi moi phuong an
{
CapNhatPATU();
DayNhiPhanKe();
}
GhiFile();
}
Cách 2:
#include <stdio.h>
#include <conio.h>
void DocFile()
{ FILE *fp = fopen(filename,"r");//mo file du lieu de doc

{
printf("%4d",C[i]);
}
{
printf("%4d",A[i]);
}
fclose(fp);
}
int S=0, P=0;
{
S = S + A[i] * X[i];
P = P + C[i] * X[i];
}
{ FOPT = P; // Cap nhat gia tri toi uu moi
XOPT[i] = X[i];
}
}
void Try(int i)//lan luot xet tat ca cac phuong an

{
for(int j=0;j<=1;j++)
{
X[i]=j;
if(i==n) CapNhatPATU();
else Try(i+1);
}
}
void GhiFile()
{
}
fclose(fp);
}
void main()
{
DocFile();
Try(1);
GhiFile();
}
* Cach 3:
#include <stdio.h>
#include <conio.h>

int S=0,P=0;
void DocFile()
{
printf("%4d",C[i]);
}
{
printf("%4d",A[i]);
}
fclose(fp);
}
{
{
X[i]=j;S=S+A[i]*X[i];P=P+C[i]*X[i];
if(i==n)
{

{ FOPT = P; //Cap nhat gia tri toi uu moi
for(int k=1; k<=n; k++) // Cap nhat phuong an toi uu moi
XOPT[k] = X[k];
}
}
else
if(S<B) Try(i+1);
S=S-A[i]*X[i];P=P-C[i]*X[i];
}
}
void GhiFile()
{ printf("%3d",XOPT[i]);
}
fclose(fp);
}
void main()
{
DocFile();
Try(1);
GhiFile();
}
Bai 24:
HD:
#include <conio.h>
#include <string.h>
char *data1="d:data1.out";
char *data2="d:data2.out";
int num1=0,num2=0;
void Sdt(int flag)//flag=0 la dem, flag=1 la ghi

{
FILE *f1=fopen(data1,"w");
FILE *f2=fopen(data2,"w");
if(flag==1) {fprintf(f1,"%d",num1);fprintf(f2,"%d",num2);}
for(int n=1;n<=4;n++)
for(int x1=0;x1<=9;x1++)
for(int x2=0;x2<=9;x2++)
for(int x3=0;x3<=9;x3++)
{
if(flag==0) num1++;
else
fprintf(f1,"n091%d.%d%d%d.%d%d
%d",n,x1,x2,x3,x3,x2,x1);
if(x1+x2+x3==4)
{ if (flag==0) num2++;
else
fprintf(f2,"n091%d.%d%d%d.%d%d
%d",n,x1,x2,x3,x3,x2,x1);
}
}
fclose(f1);fclose(f2);
}
void main()
{ Sdt(0);//dem cac so dien thoai
Sdt(1);//ghi cac so dien thoai vao file
}
Bài 25:
Chú ý: làm bài tập tương tự với đồ thị có hướng
HD:
#include <stdio.h>
const max=30;//so dinh toi da
int n;//so dinh thuc su
int mtk[max][max];//mang chua ma tran ke
int stplt=0;//bien dem so thanh phan lien thong

//mang danh dau dinh da tham roi hay chua
//tham[i]=0 la i chua tham
//tham[i]=k la i tham roi, va i thuoc thanh phan lien thong thu k
int tham[max];
char *dothi="d:dothi.in";
char *ketqua="d:ketqua.out";
void DocFile()
{ int i,j;
FILE *f=fopen(dothi,"r");//mo file dothi de doc
fscanf(f,"%d",&n);//doc so dinh cua do thi
//ban dau gan mtk=0
for(i=1;i<=n;i++)
for(j=1;j<=n;j++) mtk[i][j]=0;
//lan luot doc cac canh (i,j) trong file
while(fscanf(f,"%d%d",&i,&j)!=EOF)
mtk[i][j]=mtk[j][i]=1; //gan 1 vao vi tri tuong ung trong mtk
fclose(f);//dong file
}
void DFS1(int i)//duyet mot thanh phan lien thong chua dinh i
{
tham[i]=stplt;//danh dau i tham roi va i thuoc tplt thu stplt
for(int j=1;j<=n;j++)
if(tham[j]==0&&mtk[i][j]==1)//neu j chua tham va j ke i
DFS1(j);//tham j
}
void DFS()
{
//ban dau gan tat ca cac dinh la chua tham
for(int i=1;i<=n;i++) tham[i]=0;
for(i=1;i<=n;i++)//lan luot xet cac dinh i
if(tham[i]==0)//neu dinh i chua tham
{ stplt++;//tang so tplt
DFS1(i);//tham mot tplt chua i
}
}
void GhiFile()

{
FILE *f=fopen(ketqua,"w");//mo file ket qua de ghi
if(stplt==1) fprintf(f,"Do thi lien thong");
else
{
fprintf(f,"Do thi khong lien thong");
for(int i=1;i<=stplt;i++)
{
fprintf(f,"nThanh phan lien thong thu %d:",i);
if(tham[j]==i)//neu j thuoc tplt thu i
fprintf(f,"%4d",j);//ghi j vao tplt thu i
}
}
fclose(f);
}
void main()
{
DocFile();
DFS();
GhiFile();
}
Bài 26
* Bài 1:
+ Câu a:
#include <stdlib.h>
const max=30;
{ cout<<"nNhap so phan tu:"; cin>>n; randomize();
for(int i=1;i<=n;i++) a[i]=random(20);
}
{
for(int i=1;i<=n;i++) cout<<a[i]<<",";

}
//dieu chinh day a[i],a[i+1],...,a[n] thanh heap, biet rang a[i+1],..,a[n] da la heap
void adjust(int a[], int i, int n)
{ int x=a[i]; //cat a[i] vao bien x (bien tam)
int j=2*i; //a[j] la con cua a[i]
while(j<=n)
{ //neu a[i] co hai con thi chon a[j] la con lon nhat
if (j<n && a[j+1]>a[j]) j=j+1;
if (a[j]>x) //neu con cua a[i] la a[j] lon hon x
{
a[i]=a[j];//doi a[j] len vt a[i]
i=j;//lai xet pt a[i] moi
j=2*i;//a[j] la con cua a[i]
}
else break;//neu a[j]<=x thi ngung
}
a[i]=x;
}
void heapsort(int a[], int n)
{
/*
lan luot dieu chinh cac day
a[n/2],…,a[n]; a[n/2 + 1],…,a[n]; a[1],…,a[n]
thanh heap
*/
for(int i=n/2;i>=1;i--)
{ adjust(a,i,n);
cout<<"ni="<<i<<": ";output(a,n);
}
//lan luot dua pt lon nhat xuong vt a[n],…,a[2] bang cach hoan vi voi a[1]
//sau do giam n va lai dieu chinh a[1] den a[n] thanh heap
{ int x=a[1]; a[1]=a[j]; a[j]=x; //hoan vi a[j] voi a[1]
adjust(a,1,j-1);//dieu chinh day a[1],…,a[j-1] thanh heap
cout<<"nj="<<j<<": ";output(a,n);
}

}
void main()
{ int a[max],n;
input(a,n);
cout<<"nDay truoc khi sx:"; output(a,n);
heapsort(a,n);
cout<<"nDay sau khi sx:"; output(a,n);
}
+ Câu b:
#include <stdlib.h>
#include <conio.h>
const max=50;
randomize();
}
{
}
int sub_max(int a[], int n, int j)
{ int k=0;
if(j<=n)
{ k=j;
if (j+1<=n&&a[j+1]>a[k]) k=j+1;
if (j+2<=n&&a[j+2]>a[k]) k=j+2;
}
return k;
}
void Adjust(int a[], int i, int n)
{ int x=a[i];
while(1)
{ int k=sub_max(a,n,3*i-1);
if(k==0||a[k]<x) break;

a[i]=a[k]; i=k;
}
a[i]=x;
}
void HeapSort(int a[], int n)
{ for(int i=(n+1)/3; i>=1; i--) Adjust(a,i,n);
{ int x=a[1]; a[1]=a[j]; a[j]=x;
Adjust(a,1,j-1);
}
}
void main()
{ int a[max],n;
input(a,n);
cout<<endl<<"Day truoc khi sap:"<<endl;
output(a, n);
HeapSort(a,n);
cout<<endl<<"Day sau khi sap:"<<endl;
output(a, n);
}
Bài 27:
* Bài 2:
include <iostream.h>
#include <stdlib.h>
//#include <conio.h>
const max=50;
struct datatype
{ int l,r;
};
struct node
{ datatype data;
node * next;
};
typedef node* nodeptr;
void push(nodeptr &s, datatype x)
{ nodeptr p=new node;

p->data=x;p->next=s;s=p;
}
datatype pop(nodeptr &s)
{ if(s==NULL) {cout<<"nStack is empty!"; exit(1);}
nodeptr p=s; datatype x=p->data;
s=s->next; delete p;return x;
}
randomize();
}
{
}
void quick_sort(int a[], int l, int r)
{ nodeptr s=NULL; datatype x,y;
x.l=l; x.r=r; push(s,x);
while(s!=NULL)
{ datatype x=pop(s);
int t=a[(x.l+x.r)/2],i=x.l,j=x.r;
do
{ while(a[i]<t) i++;
while(a[j]>t) j--;
if(i<=j)
{ int temp=a[i];a[i]=a[j]; a[j]=temp;
i++; j--;
}
}while(i<=j);
if (x.l<j){y.l=x.l;y.r=j;push(s,y);}
if (i<x.r){y.l=i;y.r=x.r; push(s,y);}
}
}
void main()

{ int a[max],n,m;char ans;
do
{ input(a,n);
cout<<endl<<"Day so truoc khi sap:"<<endl;
output(a, n);quick_sort(a,1,n);
cout<<endl<<"Day so sau khi sap:"<<endl;
output(a, n);
cout<<"nTiep khong (c/k)?:"; cin>>ans;
}while(ans=='c'||ans=='C');
}
Bài 28
* Bài 3:
//tron tu nhien ba bang hai giai doan tren file
#include <stdio.h>
#include <stdlib.h>
//tao file chua n so nguyen ngau nhien tu 0 den 19
void WriteFile(char *filename, int n)
{
FILE *f; int i;
f=fopen(filename,"w");
randomize();
for (i=1;i<=n;i++)
fprintf(f,"%d ",random(20));
fclose(f);
}
//doc file chua cac so nguyen hien ra man hinh
void ReadFile(char *filename)
{
FILE *f; int x;
f=fopen(filename,"r");
printf("n");
while (fscanf(f,"%d",&x)!=EOF)
printf("%d ",x);
fclose(f);
}
//doc mot so tu file f1 ghi vao file f2,

//neu f1 da o cuoi file hoac so tiep theo nho hon so moi doc
//thi doan con trong file f1 da het, gan endsub=1
void CopyRecord(FILE *f1,FILE *f2, int &endsub)
{
int n,m; long p1,p2;
endsub=0;
if (fscanf(f1,"%d",&n)!=EOF)
{
fprintf(f2,"%d ",n);
fgetpos(f1,&p1);
if (fscanf(f1,"%d",&m)==EOF) endsub=1;
else
{
if (m<n) endsub=1;
fsetpos(f1,&p1);
}
}
else endsub=1;
}
//chep mot doan con tu f1 vao f2
void CopySub(FILE *f1,FILE *f2)
{
int endsub=0;
while (!endsub)
CopyRecord(f1,f2,endsub);
}
//tach filename thanh filename1 va filename2
void Split(char *filename, char *filename1, char *filename2)
{
int flag,n,n1; FILE *f,*f1,*f2;
f=fopen(filename,"r");f1=fopen(filename1,"w");f2=fopen(filename2,"w");
flag=1;
while (!feof(f))
{
if (flag) CopySub(f,f1);
else CopySub(f,f2);

flag=1-flag;
}
}
//tra ve so nguyen ma con tro f dang tro toi
//neu con tro o cuoi file thi gan endsub=1
int CurRecord(FILE *f, int &endsub)
{
int n; long p;
endsub=0;
fgetpos(f,&p);
if (fscanf(f,"%d",&n)==EOF) endsub=1;
else fsetpos(f,&p);
return n;
}
//tron filename1 va filename2, ghi vao filename
int Merge(char *filename1, char *filename2, char *filename)
{
FILE *f, *f1, *f2;
int numsub,endsub1,endsub2,n1,n2;
f1=fopen(filename1,"r");f2=fopen(filename2,"r");f=fopen(filename,"w");
numsub=0;
while (!feof(f1)||!feof(f2))
{
endsub1=endsub2=0;
do
{
if (!endsub1&&!endsub2)
{
if (n1<n2) CopyRecord(f1,f,endsub1);
else CopyRecord(f2,f,endsub2);
}
}while(!endsub1 && !endsub2);
if (!endsub1) CopySub(f1,f);

else if (!endsub2) CopySub(f2,f);
numsub++;
}
while (!feof(f1))
{
CopySub(f1,f);
numsub++;
}
while (!feof(f2))
{
CopySub(f2,f);
numsub++;
}
return numsub;
}
void MergeSort(char *filename)
{
char *filename1="d:temp1.txt", *filename2="d:temp2.txt";
int numsub;
do
{
Split(filename,filename1,filename2);
numsub=Merge(filename1,filename2,filename);
}while(numsub>1);
}
void main()
{
char *filename="d:test.txt";
int n;
printf("nNhap so phan tu cua day so:");
scanf("%d",&n);
WriteFile(filename,n);
ReadFile(filename);

ReadFile(filename);
}
Bài 29:
* Bài 4
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <string.h>
struct sinhvien
{
char masv[10];
int diemthi;
};
int Eof(FILE *f)
{
fpos_t fpos; sinhvien sv;
int num;//so sv doc duoc phai la 1, neu la 0 thi het file
fpos=ftell(f);
num=fread(&sv,sizeof(sv),1,f);
fseek(f,fpos,0);
return (num==0)?1:0;
}
void RandomFileSV(char *filename, int n)
{
FILE *f=fopen(filename,"wb");
sinhvien sv; char index[5];
randomize();
for(int i=1;i<=n;i++)
{
itoa(i,index,10);
strcpy(sv.masv,"DH08");
if (i<10) strcat(sv.masv,"0");
strcat(sv.masv,index);
sv.diemthi= random(11);
fwrite(&sv,sizeof(sv),1,f);

}
fclose(f);
}
void PrintFileSV(char *filename)
{
FILE *f=fopen(filename,"rb");
sinhvien sv;
//neu het file fread tra ve 0
while(!Eof(f))
{
fread(&sv,sizeof(sv),1,f);
printf("n%-10s%4d",sv.masv,sv.diemthi);
}
fclose(f);
}
int CurrentRecord(FILE* f)
{
fpos_t fpos; sinhvien sv;
fpos=ftell(f);
fread(&sv,sizeof(sv),1,f);
fseek(f,fpos,0);
return sv.diemthi;//tra ve diem thi cua sv hien hanh
}
int CopyRecord(FILE* f1, FILE* f2)
{
int n; sinhvien sv;
if (!Eof(f1))
{
fread(&sv,sizeof(sv),1,f1);
fwrite(&sv,sizeof(sv),1,f2);
}
if (Eof(f1)) return 1;
else return (CurrentRecord(f1)<sv.diemthi)?1:0;
//1 la kt doan con hoac het file
}
void CopySubFile(FILE *f1, FILE *f2)

{
while(!CopyRecord(f1,f2));
}
void SplitFile(char *filename,char *filename1, char *filename2)
{
FILE *f,*f1,*f2; int filenum;
f=fopen(filename,"rb");f1=fopen(filename1,"wb");
f2=fopen(filename2,"wb");
filenum=1;
while(!Eof(f))
{
if (filenum==1) CopySubFile(f,f1);
else CopySubFile(f,f2);
filenum=3-filenum;
}
}
int MergeFile(char *filename1,char *filename2,char *filename)
{
FILE *f,*f1,*f2;
int numsubfile,endsubfile1,endsubfile2;
numsubfile=0;
f1=fopen(filename1,"rb");f2=fopen(filename2,"rb");
f=fopen(filename,"wb");
while(!Eof(f1)&&!Eof(f2))
{
endsubfile1=endsubfile2=0;
do
{
if (CurrentRecord(f1)<CurrentRecord(f2))
endsubfile1=CopyRecord(f1,f);
else
endsubfile2=CopyRecord(f2,f);
}while(!endsubfile1&&!endsubfile2);
if (!endsubfile1) CopySubFile(f1,f);
else

if (!endsubfile2) CopySubFile(f2,f);
numsubfile++;
}
while(!Eof(f1))
{
CopySubFile(f1,f);
numsubfile++;
}
while(!Eof(f2))
{
CopySubFile(f2,f);
numsubfile++;
}
return numsubfile;
}
void MergeSort(char *file)
{
char *file1="d:test1.dat";
char *file2="d:test2.dat";
int numsubfile=0;
do
{
SplitFile(file,file1,file2);
numsubfile=MergeFile(file1,file2,file);
}while(numsubfile>1);
remove(file1);remove(file2);
}
void main()
{
char *filename="d:test.dat";
clrscr();
RandomFileSV(filename,10);
printf("nFile sv truoc khi sap xep:");
PrintFileSV(filename);

printf("nFile sv sau khi sap xep:");
PrintFileSV(filename);
getch();
}
BÀI TẬP 77: Cài đặt thuật toán Ford-Fulkerson
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
const max=20;
int dsc[max][4],c[max][max],f[max][max];
int p[max],d[max],tham[max],m,n,s,t;
char *tenfile="d:/fordfulk.txt";
//doc d/s cung tu file, m la so cung, n la so dinh
void Doc_File_DSC()
{
FILE *f=fopen(tenfile,"r");
if (f==NULL)
{
printf("nFile %s khong co",tenfile); exit(0);
}
fscanf(f,"%d%d%d%d",&n,&m,&s,&t);
for (int i=1; i<=m; i++)
{
fscanf(f,"%d%d%d%d",&(dsc[i][0]),&(dsc[i][1]),&(dsc[i][2]),&(dsc[i][3]));
}
fclose(f);
}
const vc=100; //vo cuc
//Chuyen danh sach cung sang ma tran ke co huong
void Chuyen_DSC_MTK()
{
int i,j,k;
for (i=1; i<=n; i++)
for (j=1; j<=n; j++)
{ c[i][j]=f[i][j]=0;}

for (k=1; k<=m; k++)
{
i=dsc[k][0],j=dsc[k][1]; c[i][j]=dsc[k][2];f[i][j]=dsc[k][3];
}
}
//tim duong tang luong
int Find_Path()
{
int u,v,queue[max],dau,cuoi;
for (v=1;v<=n;v++) tham[v]=0;
queue[1]=s;p[s]=s;d[s]=vc;tham[s]=1;
dau=1; cuoi=2;
while (dau!=cuoi)
{
u=queue[dau++];
for (v=1;v<=n;v++)
{
if (!tham[v])
{
if (c[u][v]>0 && f[u][v]<c[u][v]) // Gf co cung thuan (u,v)
{
p[v]=u; d[v]=(d[u]<c[u][v]-f[u][v])?d[u]:(c[u][v]-f[u]
[v]);
if (v == t) return 1;
queue[cuoi++]=v; tham[v]=1;
}
if (c[v][u]>0 && f[v][u]>0) //co cung nghich (u,v)
{
p[v]=-u; d[v]=(d[u]<f[v][u])?d[u]:f[v][u];
if (v == t) return 1;
queue[cuoi++]=v; tham[v]=1;
}
}
}
}
return 0;

}
//tang luong
void Inc_Flow()
{
int u,v,tang;
v=p[t]; u=t; tang=d[t];
while (u!=s)
{
if (v>0) f[v][u]=f[v][u]+tang;
else
{
v=-v; f[u][v]=f[u][v]-tang;
}
u=v; v= p[u];
}
}
void Max_Flow()
{
int u,v,stop,sum;
stop=0;
while (!stop)
if (Find_Path()) Inc_Flow(); else stop=1;
printf("Luong cuc dai:");
for (u=1;u<=n;u++)
{
printf("n");
for (v=1;v<=n;v++)
{
printf("%d ",f[u][v]);
}
}
sum=0;
for (u=1;u<=n;u++)
if (c[s][u]>0) sum+=f[s][u];
printf("nnGia tri luong cuc dai:%d",sum);
printf("nnLat cat:");

printf("nVT:");
for (u=1;u<=n;u++)
if (tham[u]) printf("%d ",u);
printf("nVVT:");
for (u=1;u<=n;u++)
if (!tham[u]) printf("%d ",u);
}
void main()
{
clrscr();
Doc_File_DSC();
Chuyen_DSC_MTK();
Max_Flow();
getch();
}
Bài 30
HD:
//tim cay khung nho nhat tren do thi lien thong
#include <stdio.h>
#include <conio.h>
const vc=1000;//gia tri vo cuc
int s;//dinh xuat phat
int tham[max];//tham[i]=0 la i chua tham,tham[i]=1 la i tham roi
int d[max];//d[i] kcnn tu i den cay khung
int gan[max];//gan[i]=j nghia la j la dinh cua cay khung gan i nhat
int canhck[max][3];//mang luu canh cay khung
int m=0;//so canh cay khung
int cd=0;//chieu dai cay khung
char *dulieu="d:caykhung.in";
char *ketqua="d:caykhung.out";
void DocFile()

{ int i,j,k;
FILE *f=fopen(dulieu,"r");//mo file du lieu de doc
fscanf(f,"%d%d",&n,&s);//doc so dinh n va dinh xuat phat s
//gan tri ban dau cho mtk
for(i=1;i<=n;i++)
for(j=1;j<=n;j++)
if(i==j) mtk[i][j]=0; else mtk[i][j]=vc;
//lan luot doc tu file cac canh(i,j) co trong so k
while(fscanf(f,"%d%d%d",&i,&j,&k)!=EOF)
mtk[i][j]=mtk[j][i]=k;//gan k vao vi tri tuong ung trong mtk
}
void Prim()//tim cay khung nn voi s la dinh xuat phat
{ int i,j,u,v,min;
for(i=1;i<=n;i++)
{
d[i]=mtk[s][i];gan[i]=s;tham[i]=0;
}
tham[s]=1;//danh dau s tham roi
for(i=1;i<=n-1;i++)//lan luot tham n-1 dinh con lai
{
//tim dinh u chua tham va co d[u] nho nhat de tham
min=vc;
for(j=1;j<=n;j++)
if(tham[j]==0&&d[j]<min)//neu j chua tham va d[j]<min
{ u=j;
min=d[j];
}
tham[u]=1;++m;
canhck[m][1]=u;canhck[m][2]=gan[u];canhck[m][3]=mtk[u][gan[u]];
cd=cd+canhck[m][3];
//cap nhat cac dinh v chua tham va v ke u
for(v=1;v<=n;v++)
if(tham[v]==0&&mtk[u][v]!=vc)
if(d[v]>mtk[u][v])
{

d[v]=mtk[u][v];gan[v]=u;
}
}
}
void GhiFile()
{
FILE *f=fopen(ketqua,"w");
int i,j,k;
fprintf(f,"%dt%d",m,cd);
for(i=1;i<=m;i++)
fprintf(f,"n%dt%dt%d",canhck[i][1],canhck[i][2],canhck[i][3]);
fclose(f);
}
void main()
{
DocFile();
Prim();
GhiFile();
}
Bài 31
Bài giải 31:
HD:
#include <stdio.h>
#include <math.h>
#include <conio.h>
const max=30;
int a=3,b=6;
int X[max];//chua so can tim: x1x2...xn (a<=n<=b)
int S,P,B;
int count=0;
long K=0;
void tinhK(int i)//tinh K co i chu so X1X2...Xi
{ long q=1;K=0;
for(int j=i;j>0;j--)
{
K=K+q*X[j];q=q*10;

}
}
int ktnt()//kiem tra K co la nguyen to kg?
{ int nt=1;
for(long i=2;i<=sqrt(K);i++)
if(K%i==0) {nt=0;break;}
return nt;
}
//kiem tra xem K=x1...xi co tong x1+...+xi co chia het cho S hay kg?
int kttong(int i)
{ long M=0;//M la tong cac chu so cua K
for(int j=1;j<=i;j++) M=M+X[j];
if (M%S==0) return 1;
else return 0;
}
//kiem tra K bieu dien o co so B co la so thuan nghich hay kg?
int kttn()
{ int d[max];//dm...d1 la bieu dien o co so B cua K
long T=K; int m=0;
do
{ d[++m]=T%B;T=T/B;
}while(T!=0);
int tn=1;
for(int i=1;i<=m/2;i++)
if(d[i]!=d[m-i+1]) {tn=0;break;}
return tn;
}
void Try(int i)
{ for(int j=0;j<=9;j++)
{ if((i!=1&&j!=P)||(i==1&&j!=0&&j!=P))
{
X[i]=j;
if(i>=a&&i<=b)
{ tinhK(i);
if(ktnt()==1&&kttong(i)==1&&kttn()==1)
{

printf("n%d)%ld",++count,K);
if(count%20==0) getch();
}
}
if(i<b) Try(i+1);
}
}
}
void main()
{
printf("n1.K co %d den %d chu so",a,b);
printf("n2.K la so nguyen to");
printf("n3.Cac chu so cua K phai khac P");
printf("n4.Tong cac chu so cua K phai chia het cho S");
printf("n5.Bieu dien theo co so B cua K phai la day thuan nghich");
printf("nNhap P(0->9):");scanf("%d",&P);
printf("Nhap S:");scanf("%d",&S);
printf("Nhap co so B:");scanf("%d",&B);
Try(1);
}
BÀI TẬP 82: Bài toán mã đi tuần
Mã nguồn:
#include<iostream>
using namespace std;
int bc[100][100];
int lechX[8] = {2,1,-1,-2,-2,-1,1,2};
int lechY[8] = {1,2,2,1,-1,-2,-2,-1};
int n;
void init(){
for(int i = 0; i<n; i++)
for(int j = 0; j<n; j++)
bc[i][j] = 0;
}

void print(){
cout<<"Thu tu cac buoc di cua quan ma: n";
for(int i=0; i<n; i++){
for(int j=0; j<n; j++)
cout<<bc[i][j]<<" ";
cout<<endl;
}
}
void knightTour(int j,int x, int y){
int u,v;
for(int i = 0 ;i<8; i++){
u = x + lechX[i];
v = y + lechY[i];
if(0<=u && u<n && 0<=v && v<n && bc[x][y]==0 ){
bc[u][v] = j;
if (j==n*n) print();
else knightTour(j+1,u,v);
bc[u][v] = 0;
}
}
}
void main(){
cout<<"Nhap n= ";
cin>>n;
init();
int x0= 4, y0=4;
bc[x0][y0]=1;
knightTour(2,x0,y0);
cout<<endl;

system("PAUSE");
}
Các pác có biết input như thế nào có thể cho ra output hông?
Hông biết code của mình có vấn đề hay không mà chạy hoài không có output nào cả.
Mình thấy bạn nhầm ở điều kiện
if(0<=u && u<n && 0<=v && v<n && bc[x][y]==0 )
Ở đây bc[x][y] nên được sửa thành bc[u][v].
Thêm nữa, có lẽ bạn chọn vị trí không tốt nên chạy không ra kết quả. Mình sửa hàm
KnightTour thành:
Mã nguồn:
void KnightTour(int j, int x, int y)
{
int u,v;
if (j > n*n)
{
print();
}
else
{
for (int i = 0 ;i < 8; i++)
{
u = x + lechX[i];
v = y + lechY[i];
if (0 <= u && u < n && 0 <= v && v < n && bc[u][v] == 0)
{
bc[u][v] = j;
knightTour(j+1, u, v);
bc[u][v] = 0;
}
}
}
}
và đặt x0 = 0, y0 = 0 thì chạy cho ra vô số kết quả với n = 8.
--------------------------------------------------------------------------------------------------------------
Công thức truy hồi
Xem các dãy số {xn}, {yn}, {zn} được cho theo công thức như sau:
x0=y0=z0=1
với n>=1 thì:

xn=xn-1 + 2yn-1 + 3zn-1
yn=4xn-1 + 5yn-1 + 6zn-1
zn=7xn-1 + 8yn-1 + 9zn-1
Hãy viết hàm (không đệ quy) để tính giá trị của xn, yn, zn khi biết n (nguyên không âm).
Hàm này mô tả như sau:
void EvaluateXYZ(int n, float& x, float& y, float& z);
Trong đó, các tham biến x, y, z nhận về các giá trị tương ứng của xn, yn, zn.
Bài này đơn giản là dùng 3 biến để lưu giá trị trước như sau:
Mã nguồn:
void EvaluateXYZ(int n, float &x, float &y, float &z) {
float x0 = x = 1, y0 = y = 1, z0 = z = 1;
for (int i=1; i<=n; i++) {
x = x0 + 2*y0 + 3*z0;
y = 4*x0 + 5*y0 + 6*z0;
z = 7*x0 + 8*y0 + 9*z0;
x0 = x;
y0 = y;
z0 = z;
}
}
Bài 35
HD:
#include <stdio.h>
int stplt=0;//bien dem so thanh phan lien thong
//mang danh dau dinh da tham roi hay chua
//tham[i]=0 la i chua tham
//tham[i]=k la i tham roi, va i thuoc thanh phan lien thong thu k
int tham[max];
char *dothi="d:dothi.in";
char *ketqua="d:ketqua.out";
void DocFile()
{ int i,j;

FILE *f=fopen(dothi,"r");//mo file dothi de doc
fscanf(f,"%d",&n);//doc so dinh cua do thi
//ban dau gan mtk=0
for(i=1;i<=n;i++)
for(j=1;j<=n;j++) mtk[i][j]=0;
while(fscanf(f,"%d%d",&i,&j)!=EOF)
mtk[i][j]=mtk[j][i]=1; //gan 1 vao vi tri tuong ung trong mtk
}
void DFS1(int i)//duyet mot thanh phan lien thong chua dinh i
{
tham[i]=stplt;//danh dau i tham roi va i thuoc tplt thu stplt
if(tham[j]==0&&mtk[i][j]==1)//neu j chua tham va j ke i
DFS1(j);//tham j
}
void DFS()
{
//ban dau gan tat ca cac dinh la chua tham
for(int i=1;i<=n;i++) tham[i]=0;
for(i=1;i<=n;i++)//lan luot xet cac dinh i
if(tham[i]==0)//neu dinh i chua tham
{ stplt++;//tang so tplt
DFS1(i);//tham mot tplt chua i
}
}
void GhiFile()
{
FILE *f=fopen(ketqua,"w");//mo file ket qua de ghi
if(stplt==1) fprintf(f,"Do thi lien thong");
else
{
fprintf(f,"Do thi khong lien thong");
for(int i=1;i<=stplt;i++)
{

fprintf(f,"nThanh phan lien thong thu %d:",i);
if(tham[j]==i)//neu j thuoc tplt thu i
fprintf(f,"%4d",j);//ghi j vao tplt thu i
}
}
fclose(f);
}
void main()
{
DocFile();
DFS();
GhiFile();
}
BÀI TẬP 84: Bài toán cái túi
#include <stdio.h>
#include <conio.h>
//c[i]: gia tri su dung cua vat loai i, a[i]: trong luong vat loai i
float c[100],a[100];
//x: chua phuong an trung gian, xopt: phuong an toi uu
int x[100],xopt[100];
//d: so thu tu cua loai i la d[i]
int d[100],n;//n la so loai vat
/*w la trong luong toi da tui co the chua,
weight: trong luong hien tai cua tui
fopt: gia tri hien tai lon nhat cua tui
cost: gia tri hien tai
*/
float w,weight,fopt,cost;
/* file caitui.dat co dang sau:
4 8 //n=4, b=8
5 3 2 4 //a: trong luong moi loai vat
10 5 3 6 //c: gia tri moi loai vat
*/
void ReadFile()

{
FILE *fin;
int i;
if ((fin = fopen("caitui.dat", "rt"))== NULL)
{
printf("Khong tim thay file caitui.dat.n");
return ;
}
fscanf(fin,"%d%f",&n,&w);
for (i=0;i<n;i++) fscanf(fin,"%f",&a[i]);
for (i=0;i<n;i++) fscanf(fin,"%f",&c[i]);
fclose(fin);
printf("nSo loai vat:%d",n);
printf("nTrong luong cai tui:%0.0f",w);
printf("nTrong luong cac loai vat:");
for (i=0;i<n;i++) printf("%0.0f ",a[i]);
printf("nGia tri cac loai vat:");
for (i=0;i<n;i++) printf("%0.0f ",c[i]);
}
void Init()
{
int i,j,k,t;
fopt=0;// gia tri lon nhat =0
weight=0;//trong luong ban dau cua tui=0;
for (i=0; i<n; i++)
d[i]=i+1;
for (i=0; i<n-1; i++)
{
k=i;
for (j=i+1; j<n; j++)
if (c[j]/a[j]>c[k]/a[k]) k=j;
if (k!=i)
{
t=a[i];a[i]=a[k];a[k]=t;
t=c[i];c[i]=c[k];c[k]=t;
t=d[i];d[i]=d[k];d[k]=t;
}
}

}
void KyLuc()
{
if (cost>fopt)
{
for (int i=0; i<n; i++)
{
xopt[i]=x[i]; fopt=cost;
}
}
}
void Try(int i)
{
int j,t;
t=(w-weight)/a[i];//w: suc chua cua tui
for (j=t; j>=0; j--)
{
x[i]=j;
weight=weight+a[i]*x[i];//weight:trong luong tui
cost=cost+c[i]*x[i];//cost: gia tri tui
if (i==n-1) KyLuc();
else
if (cost+c[i+1]*(w-weight)/a[i+1]>fopt) Try(i+1);
weight=weight-a[i]*x[i];
cost=cost-c[i]*x[i];
}
}
void InKq()
{
printf("nTong gia tri do vat:%0.0f",fopt);
for (int i=0; i<n; i++)
printf("nso luong do vat loai %d la %d",d[i],xopt[i]);
}
void main()
{
clrscr();
ReadFile();

Init();
Try(0);
InKq();
getch();
}
BÀI TẬP 85: Bài toán người du lịch
#include <stdio.h>
#include <conio.h>
#include <values.h>
int n;//so thanh pho
int c[100][100];//ma tran chi phi
int cmin;//chi phi nho nhat trong ma tran chi phi
int tp[100];//tp[i]=0:tp i da di qua, =1 chua di qua
int cost;//chi phi bo phan
int fopt; //gia tri ky luc, gia tri cuoi cung la gia tri toi uu
int x[100];//la mot phuong an
int xopt[100];//la phuong an toi uu
void ReadFile()
{
FILE *fin;
int i,j;
if ((fin = fopen("dulich.dat", "rt"))== NULL)
{
printf("Khong tim thay file dulich.dat.n");
return ;
}
//doc so thanh pho
fscanf(fin,"%d",&n);
//doc ma tran chi phi
for (i=0;i<n;i++)
for (j=0;j<n;j++)
fscanf(fin,"%d",&c[i][j]);
fclose(fin);
//xuat thong tin de kiem tra
printf("nSo thanh pho:%d",n);

printf("nMa tran chi phi:");
for (i=0;i<n;i++)
{
printf("n");
for (j=0;j<n;j++)
printf("%3d",c[i][j]);
}
}
void Init()
{
int i,j;
cmin=MAXINT;//so kieu int lon nhat
for (i=0;i<n;i++)
{
tp[i]=1;//tat ca tp i deu chua di qua
for (j=0;j<n;j++)//tim cmin
if ( (i!=j)&&(c[i][j]<cmin)) cmin=c[i][j];
}
fopt=MAXINT;//ky luc ban dau
cost=0;//chi phi bo phan
x[0]=0;//tp bat dau di la tp 0
}
void CNKL() //cap nhat ky luc
{
int i,s;
s=cost+c[x[n-1]][x[0]];//cong them chi phi tro ve tp dau
if (s<fopt)//neu chi phi cua hanh trinh nay < ky luc
{
fopt=s;//ghi nhan ky luc moi
for (i=0;i<n;i++) xopt[i]=x[i]; //ghi nhan hanh trinh moi
}
}
void Try(int i)
{
int j;
for (j=1;j<n;j++)
if (tp[j])
{

x[i]=j;
tp[j]=0;//tp j da duoc chon
cost=cost+c[x[i-1]][x[i]];//chi phi bo phan
if (i==n-1) CNKL();
else
if (cost+(n-i+1)*cmin<=fopt) Try(i+1);
tp[j]=1;
cost=cost-c[x[i-1]][x[i]];
}
}
void Result()
{
int i;
printf("nnChi phi nho nhat:%d",fopt);
printf("nHanh trinh co chi phi nho nhat:n");
for (i=0;i<n;i++)
printf ("%d -> ",xopt[i]+1);
printf ("%d",xopt[0]+1);
}
void main()
{
clrscr();
ReadFile();
Init();
Try(1);
Result();
getch();
}
/*
vi du ve file dulich.dat
6
0 3 93 13 33 9
4 0 77 42 21 16
45 17 0 36 16 28
39 90 80 0 56 7
28 46 88 33 0 25
3 88 18 46 92 0

Co ds la:
Chi phi nho nhat:104
Hanh trinh co chi phi nho nhat:
1->4->6->3->2->5->1
BÀI TOÁN 86: Chuyển từ ma trận kề sang danh sách kề
#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <stdlib.h>
#define MAX 10
char *dske="d:dske.out";
char *mtke="d:mtke.in";
char *dscanh="d:dscanh.out";
void chuyen_mtke()
{ int i,j,mtk[MAX][MAX],n,m=0;
FILE *fp;
fp = fopen(mtke,"r");
fscanf(fp,"%d",&n); //doc so dinh cua do thi
printf("n So dinh do thi:%d",n);
for(i=1; i<=n; i++)
for(j=1; j<=n;j++)
{ fscanf(fp,"%5d",&mtk[i][j]);
if(mtk[i][j]==1)
m++; // dem so canh cua do thi
}
fclose(fp);
printf("n Ma tran ke doc duoc:n");
for(i=1; i<=n; i++)
{ for(j=1;j<=n;j++)
printf("%5d",mtk[i][j]);
printf("n");
}
//ghi lai danh sach ke theo khuon dang
fp = fopen(dske,"w");
printf("n So dinh:%d",n);
fprintf(fp,"%5dn",n);

printf("n Danh sach ke:n");
for(i=1; i<=n; i++)
{ for(j=1;j<=n;j++)
if(mtk[i][j])
{printf("%5d",j);
fprintf(fp,"%5d",j);
}
printf("n");
fprintf(fp,"n");
}
fclose(fp);
//ghi lai danh sach canh theo khuon dang
m = m/2; //lay so canh cua do thi
fp = fopen(dscanh,"w");
fprintf(fp,"%d%5d",n,m);
printf("n So dinh : %d, so canh:%d",n,m);
printf("n Danh sach canh:");
for(i=1; i<n; i++){
for(j=i+1; j<=n; j++)
{ if(mtk[i][j])
{printf("n %3d%5d",i,j);
fprintf(fp,"n%d%5d",i,j);
}
}
fclose(fp);
}
void main()
{
chuyen_mtke();
getch();
}
BÀI TẬP 87: Chuyển từ danh sách canh sang ma trận kề, danh sách kề
#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <stdlib.h>

#define MAX 10
char *dske="d:dske.out";
char *mtke="d:mtke.out";
char *dscanh="d:dscanh.in";
void chuyen_dscanh()
{ int i,j,dsc[MAX][MAX],mtk[MAX][MAX],n,m=0;
FILE *fp;
fp = fopen(dscanh,"r");
fscanf(fp,"%d%5d",&n,&m); //doc so dinh va so canh cua do thi
printf("n So dinh do thi:%d, so canh cua do thi:%d",n,m);
for(i=1; i<=m; i++)
for(j=1; j<=m/2;j++)
fscanf(fp,"%5d",&dsc[i][j]);//doc ds canh de in ra man hinh
fclose(fp);
printf("n Danh sach canh doc duoc:n");
for(i=1; i<=m; i++)
{ for(j=1;j<=m/2;j++)
printf("%5d",dsc[i][j]);
printf("n");
}
//bat dau gan ma tran ke =0
for(i=1; i<=n; i++)
for(j=1; j<=n;j++)
mtk[i][j]=0;
fp=fopen(dscanh,"r");
fscanf(fp,"%d%5d",&n,&m); //doc so dinh va so canh cua do thi
while(fscanf(fp,"%d%d",&i,&j)!=EOF)
mtk[i][j]=mtk[j][i]=1;
fclose(fp);
//ghi lai ma tran ke theo khuon dang
fp = fopen(mtke,"w");
printf("n Ma tran ke:n");
for(i=1; i<=n; i++)

{ for(j=1;j<=n;j++)
printf("%5d",mtk[i][j]);
fprintf(fp,"%5d",mtk[i][j]);
printf("n");
fprintf(fp,"n");
}
fclose(fp);
//ghi lai danh sach ke theo khuon dang
fp = fopen(dske,"w");
printf("n Danh sach ke:n");
for(i=1; i<=n; i++)
{ for(j=1;j<=n;j++)
if(mtk[i][j])
{printf("%5d",j);
fprintf(fp,"%5d",j);
}
printf("n");
fprintf(fp,"n");
}
fclose(fp);
}
void main()
{
chuyen_dscanh();
getch();
}
Bài 36
HD:
* Cach 1:
#include <stdio.h>
#include <conio.h>

int stop=0;//stop=1 la ngung sinh day nhi phan ke tiep
void DocFile()
{
FILE *fp = fopen(filename,"r");//mo file du lieu de doc
{
printf("%4d",C[i]);
}
{
printf("%4d",A[i]);
}
fclose(fp);
}
void KhoiTao()
{
//gan phuong an hien tai ban dau: x1=x2=...=xn=0
//va phuong an toi uu ban dau: xopt[1]=xopt[2]=...=xopt[n]=0

for(int i=1; i<=n; i++)
{
X[i]=0;
XOPT[i]=0;
}
}
void DayNhiPhanKe()//tim day nhi phan ke tiep
{
int i=n;
while(i>0 && X[i]==1) {X[i]=0;i--;}
if( i==0) stop=1;
else X[i]=1;
}
int S=0, P=0;
{
S = S + A[i] * X[i];
P = P + C[i] * X[i];
}
{
FOPT = P; // Cap nhat gia tri toi uu moi
XOPT[i] = X[i];
}
}
void GhiFile()

{
}
fclose(fp);
}
void main()
{
DocFile(); KhoiTao();
while(stop==0)//lan luot xet tat ca cac day nhi phan ung voi moi phuong an
{
CapNhatPATU();
DayNhiPhanKe();
}
GhiFile();
}
* Cach 2:
#include <stdio.h>
#include <conio.h>
void DocFile()

{
printf("%4d",C[i]);
}
{
printf("%4d",A[i]);
}
fclose(fp);
}
int S=0, P=0;
{
S = S + A[i] * X[i];
P = P + C[i] * X[i];
}
{ FOPT = P; // Cap nhat gia tri toi uu moi
XOPT[i] = X[i];
}

}
{
{
X[i]=j;
if(i==n) CapNhatPATU();
else Try(i+1);
}
}
void GhiFile()
{
}
fclose(fp);
}
void main()
{
DocFile();
Try(1);
GhiFile();
}
* Cach 3:
#include <stdio.h>
#include <conio.h>

int S=0,P=0;
void DocFile()
{
printf("%4d",C[i]);
}
{
printf("%4d",A[i]);
}
fclose(fp);
}
{
{
X[i]=j;S=S+A[i]*X[i];P=P+C[i]*X[i];
if(i==n)

{
{ FOPT = P; //Cap nhat gia tri toi uu moi
for(int k=1; k<=n; k++) // Cap nhat phuong an toi uu moi
XOPT[k] = X[k];
}
}
else
if(S<B) Try(i+1);
S=S-A[i]*X[i];P=P-C[i]*X[i];
}
}
void GhiFile()
{ printf("%3d",XOPT[i]);
}
fclose(fp);
}
void main()
{
DocFile();
Try(1);
GhiFile();
}
Bài 38
#include <stdio.h>
#include <math.h>
#include <conio.h>
int count=0;

/* kiem tra K co la nguyen to kg? */
int ktnt(long K)
{ int nt=1;
if(K==1)
nt=0;
for(long i=2;i<=sqrt(K);i++)
if(K%i==0) {nt=0;break;}
return nt;
}
/* ktra cac chu so cua K khac 0 va nguyen to */
int ktChuso(long K)
{int cs,flag=1;
while(K>0)
{
cs=K%10;
K=K/10;
if(cs==0||ktnt(cs)==0)
flag=0;
}
if(flag)
return 1;
else
return 0;
}
/* Kiem tra tong cac chu so cua K co la ngto */
int ktTong(long K)
{long M=0;//M la tong cac chu so cua K
int cs;
while(K>0)
{
cs=K%10;
K=K/10;
M+=cs;
}
if(ktnt(M))

return 1;
else
return 0;
}
/* Dao nguoc so K cung la ngto */
int ktDaoso(long K)
{int cs;
long Sodao=0;
while(K>0)
{
cs=K%10;
K=K/10;
Sodao=Sodao*10+cs;
}
if(ktnt(Sodao))
return 1;
else
return 0;
}
/* tim so K */
void TimK()
{
for(long K=10000;K<=99999;K++)
{ if(ktnt(K)==1&&ktTong(K)==1&&ktChuso(K)==1&&ktDaoso(K)==1)
{
printf("n%d)%ld",++count,K);
if(count%20==0) getch();
}
}
}
void main()
{
printf("n1.K la so co 5 chu so");
printf("n2.K la so nguyen to");
printf("n3.Dao nguoc cac chu so cua K cung la so nguyen to");

printf("n4.Tong cac chu so cua K cung la so nguyen to");
printf("n5.Cac chu so trong K deu khac 0 va la so ngto 1 chu so");
TimK();getch();
}
bai 6 trang 103: vd pt 2x1+3x2+3x3=5 (n=3,b=5, a1=2, a2=a3=3)
se co hai nghiem la: x=(1,0,1) va x=(1,1,0)
#include <stdio.h>
#include <conio.h>
void init()
{
{
printf("a%d=",i+1); scanf("%d",&a[i]);
}
count=0; s=0;
}
void result()
{
count++;
}
void Try(int i)
{
for (int j=0; j<=1; j++)
{
{
if (i==n-1)
{
if (s==b) result();
}
else Try(i+1);

}
}
}
void main()
{
clrscr();
init();
Try(0);
getch();
}
bai 7 trang 103
vd pt: x1+2x2+3x3=20 (n=3,b=20, a1=1,a2=2,a3=3)
se co 44 nghiem la: x=(0,1,6),.., x=(2,2,4),...,x=(20,0,0)
#include <stdio.h>
#include <conio.h>
void init()
{
{
printf("a%d=",i+1);
scanf("%d",&a[i]);
}
count=0; s=0;
}
void result()
{
count++;
}
void Try(int i)
{
for (int j=0; j<=b/a[i]; j++)//cac gia tri x[i] co the nhan

{
{
if (i==n-1)
{
if (s==b) result();
}
else Try(i+1);
}
}
}
void main()
{
clrscr();
init();
Try(0);
getch();
}
bai 9 trang 104
vd: N=5, tach N thanh 1 so, 2 so, 3 so, 4 so, 5 so
5, 1+4, 2+3, 1+1+3, 1+2+2, 1+1+1+2, 1+1+1+1+1
#include <stdio.h>
#include <conio.h>
int x[100],N,count,s,k,n;
void init()
{
printf("N="); scanf("%d",&N);
count=0; s=0; k=1; n=0;
}
void result()
{
count++;

}
void Try(int i)
{
for (int j=k; j<=N; j++)//cac kha nang cua x[i]
{
if (s<N)
{
s=s+x[i]; k=j; n++; //cap nhat bien trang thai s,k,n
if (s==N) result();
else if (s<N) Try(i+1);
s=s-x[i]; n--; //tra lai gia tri cu cua bien trang thai s
}
}
}
void main()
{
clrscr();
init();
Try(0);
getch();
}
bai 10 trang 104: hinh vuong than bi
Y tuong: (moi ma phuong la mot hoan vi)
- tim tat ca cac hoan vi cua tap {1,...,n*n}
- Kiem tra hoan vi nao la ma phuong thi in hoan vi do
#include <stdio.h>
#include <conio.h>
int x[100], b[100],n,count;
int a[10][10];
void init()
{
printf("n=");
scanf("%d",&n);
for (int i=0; i<n*n; i++) b[i]=1; //i chua su dung
count=0;
}

int test() //kiem tra hoan vi co la ma phuong
{
int i, j, k, s, s0, s1, s2;
//doi hoan vi thanh ma tran de de kiem tra t/c ma phuong
i=0; j=0;
for (k=0;k<n*n;k++)
{
a[i][j]=x[k]; j++;
if (j==n) {i++; j=0;}
}
//kiem tra tong moi dong phai bang nhau
s0=0;//gia tri dong 0
for (j=0;j<n;j++)
s0=s0+a[0][j];
for (i=1;i<n;i++)
{
s=0;//gia tri dong i
for (j=0;j<n;j++)
s=s+a[i][j];
//neu dong i khac dong 0 thi khong phai ma phuong
}
//kiem tra cot
s0=0;//gia tri cot 0
for (i=0;i<n;i++)
s0=s0+a[i][0];
for (j=1;j<n;j++)
{
s=0;//gia tri cot j
for (i=0;i<n;i++)
s=s+a[i][j];
//neu cot j khac cot 0 thi khong phai ma phuong
}
//kiem tra duong cheo

s1=0,s2=0;
for (i=0;i<n;i++)
{
s1=s1+a[i][i];
s2=s2+a[i][n-1-i];
}
if (s1!=s2) return 0;
return 1; //hoan vi la ma phuong
}
void result()
{
if (test())
{
count++;
printf("nMa phuong %d:n",count);
{
for (int j=0;j<n;j++)
printf("%3d",a[i][j]);
printf("n");
}
}
}
void Try(int i)
{
for (int j=0; j<n*n; j++)
{
if (b[j])
{
x[i]=j+1; b[j]=0;//j su dung roi
if (i==n*n-1) result();
else Try(i+1);
b[j]=1; //tra lai trang thai cu, j chua su dung
}
}
}

void main()
{
clrscr();
init();
Try(0);
getch();
}

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