l*nd_lele

class Solution {
    
    public long maxSumWithK(long a[], long n, long k)
    {
        long ans = Long.MIN_VALUE;
        long sum1 = 0;
        long sum2 = 0;
        int j = 0;
        
        for(int i = 0 ;i<n;i++){
            sum1+=a[i];
            
            if(i-j+1 == k){
                ans = Math.max(ans,sum1);
            }else if(i-j+1 > k){
                sum2 += a[j++];
                
                if(sum2 < 0){
                    sum1 -= sum2;
                    sum2 = 0;
                }
              ans = Math.max(ans,sum1);
            }
        }
        
        return ans;
    }
}