Merge Sort Geeks For Geeks Code Example

Example 1: merge sort algo

def mergeSort(arr):      if len(arr) >1:          mid = len(arr)//2 # Finding the mid of the array          L = arr[:mid] # Dividing the array elements           R = arr[mid:] # into 2 halves             mergeSort(L) # Sorting the first half          mergeSort(R) # Sorting the second half             i = j = k = 0                    # Copy data to temp arrays L[] and R[]          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                    # Checking if any element was left          while i < len(L):              arr[k] = L[i]              i+= 1             k+= 1                    while j < len(R):              arr[k] = R[j]              j+= 1             k+= 1    # Code to print the list  def printList(arr):      for i in range(len(arr)):                  print(arr[i], end =" ")      print()     # driver code to test the above code  if __name__ == '__main__':      arr = [12, 11, 13, 5, 6, 7]       print ("Given array is", end ="\n")       printList(arr)      mergeSort(arr)      print("Sorted array is: ", end ="\n")      printList(arr)

Example 2: merge sort algorithm

/*       a[] is the array, p is starting index, that is 0,      and r is the last index of array.  */  #include <stdio.h>  // lets take a[5] = {32, 45, 67, 2, 7} as the array to be sorted.  // merge sort function void mergeSort(int a[], int p, int r) {     int q;     if(p < r)     {         q = (p + r) / 2;         mergeSort(a, p, q);         mergeSort(a, q+1, r);         merge(a, p, q, r);     } }  // function to merge the subarrays void merge(int a[], int p, int q, int r) {     int b[5];   //same size of a[]     int i, j, k;     k = 0;     i = p;     j = q + 1;     while(i <= q && j <= r)     {         if(a[i] < a[j])         {             b[k++] = a[i++];    // same as b[k]=a[i]; k++; i++;         }         else         {             b[k++] = a[j++];         }     }        while(i <= q)     {         b[k++] = a[i++];     }        while(j <= r)     {         b[k++] = a[j++];     }        for(i=r; i >= p; i--)     {         a[i] = b[--k];  // copying back the sorted list to a[]     }  }  // function to print the array void printArray(int a[], int size) {     int i;     for (i=0; i < size; i++)     {         printf("%d ", a[i]);     }     printf("\n"); }   int main() {     int arr[] = {32, 45, 67, 2, 7};     int len = sizeof(arr)/sizeof(arr[0]);       printf("Given array: \n");     printArray(arr, len);          // calling merge sort     mergeSort(arr, 0, len - 1);       printf("\nSorted array: \n");     printArray(arr, len);     return 0; }