题目链接
翻译
translation
题解
先用 \(2\) 然后用 \(1\) 补来凑n/2就行。
挺显然的一个贪心。
代码
#include <bits/stdc++.h>
#define lson l,mid,rt*2
#define rson mid+1,r,rt*2+1
#define LL long long
using namespace std;
const int N = 100;
int a[N+10];
int main(){
ios::sync_with_stdio(0),cin.tie(0);
int T;
cin >> T;
while (T--){
int n;
cin >> n;
int cnt[3];
cnt[1] = cnt[2] = 0;
for (int i = 1;i <= n; i++){
cin >> a[i];
cnt[a[i]]++;
}
int goal = cnt[1] + cnt[2]*2;
if (goal%2==1){
cout <<"NO"<<endl;
}else{
goal/=2;
int x,y;
//x*2+y = goal
int t = goal;
x = goal/2;
x = min(x,cnt[2]);
t-=x*2;
if (t<=cnt[1]){
cout <<"YES"<<endl;
continue;
}
cout <<"NO"<<endl;
}
}
return 0;
}