Sliding Window Sum

Time Complexity O(n), Space Complexity O(1)

#include <stdio.h>

void sliding_window_sum(int arr[], int n, int k) {
    int l = 0, r = 0, i = 0;
    int window_size_sum = 0;
    while (r < n) {
        window_size_sum += arr[r];
        if ((r-l) == k-1) {
            printf("%d ", window_size_sum);
            window_size_sum -= arr[l];
            l+=1;
        }
        r+=1;
    }
}

int main() {
    int n, k, arr[100];
    scanf("%d %d", &n, &k);
    for (int i = 0; i < n; i++) scanf("%d", &arr[i]);

    sliding_window_sum(arr, n, k);
    return 0;
}

Solving Approach