题解 | 子段和

#include<bits/stdc++.h>

using namespace std;

const int N = 5e5+5;

int n;
int a[N];

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin>>n;
    for(int i=1;i<=n;i++) cin>>a[i];
    for(int i=1;i<=n;i++)
        if(a[i] == 0){
            cout<<"NO";
            return 0;
        }
    sort(a+1,a+n+1);
    int i = 1;
    bool flag = true;
    while(i<n && a[i] + a[i+1] != 0) i++;
    if(i == n) flag = true;
    else{
        bool f = false;
        for(int j = i+2; j<=n ;j++){
            if(a[j] != a[i+1]){
                f = true;
                break;
            }
            
        }
        if(!f) flag = false;
    }
    cout<<(flag?"YES":"NO");
    return 0;
}