mKqkke - Online C Compiler & Debugging Tool

#include <stdio.h>

int main() {
    const int max_n = 200000;

    int N, Q;
    scanf("%d %d", &N, &Q);

    int a[max_n + 1];
    for (int i = 1; i < N + 1; i++) {
        scanf("%d", &a[i]);
    }

    // TODO: declare and calculate prefix sum
	int p[max_n + 1];
	p[0]=0;
	for (int i = 1; i < N + 1; i++) {
		p[i]=p[i-1]+a[i];
    }
    while (Q--) {
        int l, r;
        scanf("%d%d", &l, &r);
        // TODO: calculate sum using prefix sum, i.e.
        //       a[l] + a[l+1] + ... + a[r]
		int sum=p[r]-p[l-1];
        printf("%d\n", sum);
    }

    return 0;
}