前缀和加二分解法

先算出前缀和，在二分查找，上代码

#include <bits/stdc++.h>
using namespace std ;
const int N = 1e6 ;
int a[N] , b[N];
int n ;
void solve() {
    cin >> n ;
    for(int i = 1 ; i <= n ; i++) {
        cin >> a[i] ;
        b[i] = b[i - 1] + a[i] ;
    }
    int l = 1 ;
    int r = n ;
    while(l <= r) {
        int mid = (l + r) / 2 ;
        if(b[mid] <= b[n] - b[mid]) {
            if(b[mid] == b[n] - b[mid]) {
                cout << "Yes" << endl ;
                return ;
            }
            l = mid + 1 ;
        }
        else r = mid - 1 ;
    }
    cout << "No" << endl ;
}
int main () {
    int T ;
    cin >> T ;
    while(T--) solve() ;
    return 0 ;
}