![Merge Sort How Code Works
• Pseudocode for MergeSort
As we know, merge sort works on the divide and conquer approach. It repeatedly
divides the array into smaller parts until it is left with a single element. Now let us
see the pseudocode of merge sort.
• Step 1: Declare the variable low and high to mark the start and end of the array.
• Step 2: Low will equal 0, and high will equal array size -1.
• Step 3: Calculate mid using low + high / 2.
• Step 4: Call the mergeSort function on the part (low, mid) and (mid+1, high).
• Step 5: This calling will continue till low<high is satisfied.
• Step 6: Finally, call the merge function to merge these two halves.
• Implement the Merge Sort In Python
def merge_sort(arr):
if len(arr) > 1:
mid = len(arr) // 2
L = arr[:mid]
R = arr[mid:]
merge_sort(L)
merge_sort(R)
i = j = k = 0
while i < len(L) and j < len(R):
if L[i] < R[j]:
arr[k] = L[i]
i += 1
else:
arr[k] = R[j]
j += 1
k += 1
while i < len(L):
arr[k] = L[i]
i += 1
k += 1
while j < len(R):
arr[k] = R[j]
j += 1
k += 1
arr = [12, 11, 13, 5, 6, 7]
merge_sort(arr)
print(arr)](https://image.slidesharecdn.com/mergesortgroup-5-240330165333-94ab3419/85/Data-Structure-Marge-sort-Group-5-pptx-so-4-320.jpg)
Data Structure Marge sort Group 5 pptx so
- 2. Introduction • Merge sort is a popular sorting algorithm that follows the divide- and-conquer approach. The algorithm works by dividing the input array into two halves, sorting each half separately, and then merging the two sorted halves back into a single sorted array.And is known for its stability and efficiency on large datasets. It is commonly used in various applications, including sorting massive amounts of data, parallel computing, and external sorting. In this algorithm, the main operations are merging and splitting the array, making it easy to implement and understand.
- 3. MERGE SORT ALGORITHM Top-down Approach It starts at the top and works its way down, splitting the array in half, making a recursive call, and merging the results until it reaches the bottom of the array tree.
- 4. Merge Sort How Code Works • Pseudocode for MergeSort As we know, merge sort works on the divide and conquer approach. It repeatedly divides the array into smaller parts until it is left with a single element. Now let us see the pseudocode of merge sort. • Step 1: Declare the variable low and high to mark the start and end of the array. • Step 2: Low will equal 0, and high will equal array size -1. • Step 3: Calculate mid using low + high / 2. • Step 4: Call the mergeSort function on the part (low, mid) and (mid+1, high). • Step 5: This calling will continue till low<high is satisfied. • Step 6: Finally, call the merge function to merge these two halves. • Implement the Merge Sort In Python def merge_sort(arr): if len(arr) > 1: mid = len(arr) // 2 L = arr[:mid] R = arr[mid:] merge_sort(L) merge_sort(R) i = j = k = 0 while i < len(L) and j < len(R): if L[i] < R[j]: arr[k] = L[i] i += 1 else: arr[k] = R[j] j += 1 k += 1 while i < len(L): arr[k] = L[i] i += 1 k += 1 while j < len(R): arr[k] = R[j] j += 1 k += 1 arr = [12, 11, 13, 5, 6, 7] merge_sort(arr) print(arr)
- 5. Summary • Merge Sort is a sorting algorithm that uses the divide-and-conquer approach to sort an array. It is efficient for large data sets. Merge Sort first divides the input array into smaller sub-arrays until each sub-array contains only one element. Overall, Merge Sort is a reliable and efficient sorting algorithm that is widely used in many applications. • Disadvantages of Merge Sort • Merge sort is not efficient for sorting input of large size if you are having low stack space. • Merge sort while sorting the array goes through the entire process even if the array is sorted.