题解 | 【模板】静态区间和（前缀和）

#include <iostream>
using namespace std;

int main() {
    int n, q, l, r, tmp;
    cin >> n >> q;
    auto* a = (long int*)malloc(sizeof(long int)*(n+1));//数组a存储前n个元素之和
    a[0] = 0;
    for(int i = 1; i <= n; i++){
        cin >> tmp;      
        a[i] = a[i-1]+tmp;  
    }
    for(int i = 0; i < q; i++){
        cin >> l >> r;
        cout << a[r] - a[l-1] << endl;
    }
    return 0;
}
// 64 位输出请用 printf("%lld")