Comparative analysis-of-dynamic-and-greedy-approaches-for-dynamic-programming

International Journal of Modern Trends in Engineering and
Research
www.ijmter.com
e-ISSN: 2349-9745
@IJMTER-2014, All rights Reserved 5
Comparative Analysis of Dynamic and Greedy
Approaches for Dynamic Programming
Jay Vala1
, Dhara Monaka2
, Jaymit Pandya3
1
Asst. Prof., I.T. Department, G H Patel College of Engg & Tech, jayvala1623@gmail.com
2
Asst. Prof., B.C.A. Department, Nandkunvarba Mahila College, dhara.monaka123@gmail.com
3
Asst. Prof., I.T. Department, G H Patel College of Engg & Tech, erpandyajaymit@gmail.com
Abstract— This paper analyze few algorithms of the 0/1 Knapsack Problem and fractional
knapsack problem. This problem is a combinatorial optimization problem in which one has
to maximize the benefit of objects without exceeding capacity. As it is an NP-complete
problem, an exact solution for a large input is not possible. Hence, paper presents a
comparative study of the Greedy and dynamic methods. It also gives complexity of each
algorithm with respect to time and space requirements. Our experimental results show that
the most promising approaches are dynamic programming.
Keywords- knapsack, dynamic programming, greedy programming, NP-Complete,
complexity
I. INTRODUCTION
The knapsack problem or rucksack problem is a problem in combinatorial optimization:
Given a set of items, each with a mass and a value, determine the number of each item to
include in a collection so that the total weight is less than or equal to a given limit and the
total value is as large as possible. It derives its name from the problem faced by someone who
is constrained by a fixed-size knapsack and must fill it with the most valuable items [1]
.
The 0-1 knapsack problem can solve using a partitioning algorithm for finding break item,
weak reduction, strong upper bound, finding the solution vector and minimality.
II. DIFFERENT APPROACHES TO PROBLEM
1) Greedy Approach
A thief robbing a store and can carry a maximal weight of w into their knapsack. There are n
items and ith
item weigh wi and is worth vi dollars. What items should thief take? This
version of problem is known as Fractional knapsack problem. The setup is same, but the thief
can take fractions of items, meaning that the items can be broken into smaller pieces so that
thief may decide to carry only a fraction of xi of item i, where 0 ≤ xi ≤ 1[2][3]
.
2) Dynamic Approach
Again a thief robbing a store and can carry a maximal weight of w into their knapsack. There
are n items and ith item weigh w i and is worth vi dollars. What items should thief take? This
version of problem is known as 0-1 knapsack problem. The setup is the same, but the items

International Journal of Modern Trends in Engineering and Research(IJMTER)
Volume 01, Issue 01, July- 2014
e-ISSN: 2349-9745
may not be broken into smaller pieces, so thief may decide either to take an item or to leave it
(binary choice), but may not take a fraction of an item [2][3]
.
III. GREEDY ALGORITHM
It is as follows.
1. Calculate Vi = vi/si for i=1,2,…,n
2. Sort the items by declaring Vi
3. Find j such that s1+s2+…..+ sn<= S < s1+s2+…..+ sn+1
4.
IV. DYNAMIC ALGORITHM
It is as follows.
for i=1 to n
if si < = s
if vi + V[i-1,s- si] > V[i-1, s]
V[i,s] = vi + V[i-1,s- si]
else
V[i,s] = V[i-1,s]
else V[i,s] = V[i-1,s]
V. RESULT ANALYSIS
Implemented knapsack problem with different values of weight and profit or value in Turbo C. If
we consider a data value is w={1, 2, 5}, v={1, 6, 18} and Carrying capacity W= 7 then output of
greedy is:
Fig. 1 Solved by Greedy approach
Same data values and solving by Dynamic programming.

e-ISSN: 2349-9745
Fig. 2 Solved by Dynamic programming
After implemented knapsack problem in c programming for different values of weight and profit.
Result of both methods gives same optimal solution and different time.
Method Input Data Capacity Profit Time
Greedy
W={1,3,4,5}
V={1,4,5,6}
9 11 15.86
W={1,2,5,6,7} ,
V={1,6,18,20,28}
11 40 25.73
W={10,20,30,40,50}
V={10,30,64,50,60}
100 156 21.68
Dynamic
W={1,3,4,5}
V={1,4,5,6}
9 11 17.69
W={1,2,5,6,7} ,
V={1,6,18,20,28}
11 40 18.47
W={10,20,30,40,50}
V={10,30,64,50,60}
100 156 19.65
VI. CONCLUSION
In this paper we conclude that for particular one knapsack problem we can implement two
methods greedy and dynamic. But when we implemented both method for different dataset values
then we notice something like, we consider comparison parameter as optimal profit or total value
for filling knapsack using available weight then dynamic and greedy both are gaining same profit.
If we consider time then dynamic take less amount of time compare with greedy. So we can
conclude that dynamic is better than greedy with respect to time.
REFERENCES
[1]. George B. Dantzig, Discrete-Variable Extremum Problems, Operations Research Vol. 5,
No. 2, April 1957, pp. 266–288,doi:10.1287/opre.5.2.266
[2] Gossett, Eric. Discreet Mathematics with Proof. New Jersey: Pearson Education Inc.,
2003.

e-ISSN: 2349-9745
[3] Levitin, Anany. The Design and Analysis of Algorithms. New Jersey: Pearson Education
Inc., 2003.
[4] Mitchell, Melanie. An Introduction to Genetic Algorithms. Massachusettss: The MIT
Press, 1998.
[5] Obitko, Marek. ―Basic Description.‖ IV. Genetic Algorithm. Czech Technical
University (CTU). http://cs.felk.cvut.cz/~xobitko/ga/gaintro.html
[6] Different Approaches to Solve the 0/1 Knapsack Problem. Maya Hristakeva, Dipti
Shrestha; Simpson Colleges

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