Timus 1330. Intervals

原题：1330

题意：给出n个数，m个问题（x, y)，求第x到第y个数的和

解法：前缀和

#include <iostream>using namespace std;int a[20000] = {0}, n, m;int main() {    cin >> n;    for (int i = 1; i <= n; i++) {        int x;        cin >> x;        a[i] = a[i-1]+x;    }    cin >> m;    for (int i = 1; i <= m; i++) {        int x, y;        cin >> x >> y;        cout << a[y]-a[x-1] << endl;    }}