In this article, we will learn about the solution to the problem statement given below.
Problem statement − We are given an array, we need to sort it using the concept of merge sort by iteration.
Here we place the maximum element at the end. This is repeated until the array is sorted.
Now let’s observe the solution in the implementation below −
# iterative way def mergeSort(a): current_size = 1 # traversing subarrays while current_size < len(a) - 1: left = 0 # subarray being sorted while left < len(a)-1: # calculating mid value mid = left + current_size - 1 # current_size right = ((2 * current_size + left - 1, len(a) - 1)[2 * current_size + left - 1 > len(a)-1]) # Merge merge(a, left, mid, right) left = left + current_size*2 # Increasing sub array size current_size = 2 * current_size # Merge def merge(a, l, m, r): n1 = m - l + 1 n2 = r - m L =  * n1 R =  * n2 for i in range(0, n1): L[i] = a[l + i] for i in range(0, n2): R[i] = a[m + i + 1] i, j, k = 0, 0, l while i < n1 and j < n2: if L[i] > R[j]: a[k] = R[j] j += 1 else: a[k] = L[i] i += 1 k += 1 while i < n1: a[k] = L[i] i += 1 k += 1 while j < n2: a[k] = R[j] j += 1 k += 1 # Driver code a = [2,5,3,8,6,5,4,7] mergeSort(a) print("Sorted array is:") for i in range(len(a)): print (a[i],end=" ")
Sorted array is 2 3 4 5 5 6 7 8
All the variables are declared in the local scope and their references are seen in the figure above.
In this article, we have learned about how we can make a Python Program for Iterative Merge Sort