Smallest subarray with sum greater than x

Given an array of integers (A[])  and a number x, find the smallest subarray with sum greater than the given value.

Note: The answer always exists. It is guaranteed that x doesn't exceed the summation of a[i] (from 1 to N).

Example 1:

Input:
A[] = {1, 4, 45, 6, 0, 19}
x  =  51
Output: 3
Explanation:
Minimum length subarray is 
{4, 45, 6}

Example 2:

Input:
A[] = {1, 10, 5, 2, 7}
   x  = 9
Output: 1
Explanation:
Minimum length subarray is {10}

 

method: sliding window

• Maintain l and r index to store and print these values 
• Iterate the complete array.
• Add array elements to current sum (int c)
• If current sum becomes greater than x, check the length of the subarray(int mi) and if it is min found till now update it,and even  subtract a[l] from subarray and increment l
• if current sum is less than x, then add a[r] to the subarray and increment r
• return the min length of the subarray

c++ implementation:

   int sb(int a[], int n, int x)
    {
        int l=0;int r=0;int c=0;int mi=INT_MAX;
        while(r<=n)
        {
            if(c>x)
           {
                if(mi>r-l)
                mi=r-l;
                
                c=c-a[l];
                l++;
               
           }
            else
            {
                c=c+a[r];
                r++;
            }
        }
        
        return mi;
    }

Time Complexity: O(n) 

space Complexity: O(1)