题目:

这道题很简单，直接根据题目无脑套公式
代码：

#include<bits/stdc++.h>
using namespace std;
const int N = 1e5 + 9;
using ll = long long;
ll a[N], perfix[N];
int main()
{ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);//取消同步输入输出流int n; cin >> n;//根据题目定义n，a数组的长度for (int i = 1; i <= n; i++){cin >> a[i];//给a数组初始化值}int m; cin >> m;//根据题目，输入询问次数for (int i = 1; i <= n; i++){perfix[i] = perfix[i - 1] + a[i];//求前缀和}while (m--){int l, r; cin >> l >> r;//给出范围求值cout << perfix[r] - perfix[l - 1] << '\n';//求值}return 0;
}