C Exercises: Find the maximum circular subarray sum of a given array

C Array: Exercise-51 with Solution

Write a program in C to find the maximum circular subarray sum of a given array.

Pictorial Presentation:

Sample Solution:

C Code:

#include <stdio.h>
int kadane(int arr1[], int n);

int SumOfMxCircur(int arr1[], int n)
{
   int maxKadaneSum  = kadane(arr1, n);
   int maxWrap = 0, i;
   for (i=0; i<n; i++)
   {
        maxWrap += arr1[i]; 
        arr1[i] = -arr1[i];  
   }
   maxWrap = maxWrap + kadane(arr1, n);
   return (maxWrap > maxKadaneSum)? maxWrap: maxKadaneSum;
}
int kadane(int arr1[], int n)
{
    int maxUpto  = 0, maxAtPos = 0;
    int i;
    for (i = 0; i < n; i++)
    {
        maxAtPos = maxAtPos + arr1[i];
        if (maxAtPos < 0)
            maxAtPos = 0;
        if (maxUpto < maxAtPos)
            maxUpto = maxAtPos;
 }           
   return maxUpto;
}
 
int main()
{
      int arr1[] =  {10, 8, -20, 5, -3, -5, 10, -13, 11};

    int n = sizeof(arr1)/sizeof(arr1[0]);
	int i;
 //------------- print original array ------------------	
	printf("The given array is :  ");
	for(i = 0; i < n; i++)
	{
	printf("%d  ", arr1[i]);
    } 
	printf("\n");
//------------------------------------------------------ 	
    printf("The maximum circular sum in the above array is:  %d\n", SumOfMxCircur(arr1, n));
    return 0;
}

Sample Output:

The given array is :  10  8  -20  5  -3  -5  10  -13  11  
The maximum circular sum in the above array is:  29

Flowchart:

C Programming Code Editor:

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