HDU 2509 Be the Winner——反尼姆博弈

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
const int maxn = 1000;
int n, a[maxn];
int main() {
    while (~scanf("%d", &n)) {
        int ans = 0;
        bool flag = false;
        for (int i = 1; i <= n; i++) {
            scanf("%d", &a[i]);
            ans ^= a[i];
            if (a[i] > 1) flag = true;
        }
        if ((ans && flag) || (!ans && !flag)) printf("Yes\n");
        else printf("No\n");
    }
    return 0;
}