C++ 前缀和

#include 
#include 

using namespace std;

const int N = 100010;

int n,m;
int a[N], s[N];

int main()
{
    scanf("%d%d", &n, &m);
    for ( int i = 1; i <= n; i++ ) scanf("%d", &a[i]);
    for ( int i = 1; i <= n; i++ ) s[i] = s[i - 1] + a[i];  // 前缀和的初始化
    
    while ( m-- )
    {
        int l, r;
        scanf("%d%d", &l, &r);
        printf("%dn", s[r] - s[l - 1]);    // 计算区间和
    }
    
    return 0;
}