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Mahendra KumararraysDSAlogicβ’β’β’

Merge Sort is one of the most popular sorting algorithms that is based on the principle of the Divide and Conquer Algorithms.

A divide and conquer algorithm is a strategy for solving a large problem by

- breaking the problem into smaller sub-problems
- solving the sub-problems, and
- Combine them to get the desired output.

```
def mergeSort(array):
if len(array) > 1:
# r is the point where the array is divided into two subarrays
r = len(array)//2
L = array[:r]
M = array[r:]
# Sort the two halves
mergeSort(L)
mergeSort(M)
i = j = k = 0
# Until we reach either end of either L or M, pick larger among
# elements L and M and place them in the correct position at A[p..r]
while i < len(L) and j < len(M):
if L[i] < M[j]:
array[k] = L[i]
i += 1
else:
array[k] = M[j]
j += 1
k += 1
# When we run out of elements in either L or M,
# pick up the remaining elements and put in A[p..r]
while i < len(L):
array[k] = L[i]
i += 1
k += 1
while j < len(M):
array[k] = M[j]
j += 1
k += 1
# Print the array
def printList(array):
for i in range(len(array)):
print(array[i], end=" ")
print()
# Driver program
if __name__ == '__main__':
array = [6, 5, 12, 10, 9, 1]
mergeSort(array)
print("Sorted array is: ")
printList(array)
```