题解 | 【模板】静态区间和（前缀和）

#include <stdio.h>
#include <stdlib.h>

int main(void) {
    int n, q;
    scanf("%d%d", &n, &q);
    //一行n个a数表示数组长度，q个区间询问数组
    long long* a = (long long*)malloc((n + 1) * sizeof(long long));
    long long* prefix = (long long*)malloc((n + 1) * sizeof(long long));
    prefix[0] = 0;
    for (int i = 1; i <= n; i++){
        scanf("%lld", &a[i]);   //数组中每个数的大小
        prefix[i] = prefix[i-1] + a[i];
    }
    for (int j = 0; j < q; j++){
        int l, r;
        
        scanf("%d%d", &l, &r);
        long long sum = prefix[r] - prefix[l-1];
        printf("%lld\n", sum);
    }
    free(a);
    free(prefix);
    return 0;
}