#include <iostream>
#include <vector>
using namespace std;
int maxSumSubarray(int arr[], int n, int k) {
int maxSum = 0, currentSum = 0;
for (int i = 0; i < k; i++)
maxSum += arr[i];
currentSum = maxSum;
for (int i = k; i < n; i++) {
currentSum += arr[i] - arr[i - k];
maxSum = max(maxSum, currentSum);
}
return maxSum;
}
int main() {
int arr[] = {1, 4, 2, 10, 2, 3, 1, 0, 20};
int n = sizeof(arr) / sizeof(arr[0]);
int k = 4;
int result = maxSumSubarray(arr, n, k);
cout << "Maximum sum subarray of size " << k << ": " << result << endl;
return 0;
}