BZOJ 3895: 取石子[SG函数 搜索]

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;
typedef long long ll;
const int N=51,M=50055;
inline int read(){
    char c=getchar();int x=0,f=1;
    while(c<‘0‘||c>‘9‘){if(c==‘-‘)f=-1;c=getchar();}
    while(c>=‘0‘&&c<=‘9‘){x=x*10+c-‘0‘;c=getchar();}
    return x*f;
}
int n,f[N][M];
 
int dfs(int a,int b){
    int &now=f[a][b];
    if(now!=-1) return now;
    if(a==0) return now=b&1;
    if(b==1) return now=dfs(a+1,0);
     
    if(a && !dfs(a-1,b) ) return now=1;
    if(b && !dfs(a,b-1) ) return now=1;
    if(a && b && !dfs(a-1,b+1) ) return now=1;
    if(a>=2 && !dfs(a-2,b+2+(b!=0)) ) return now=1;
    return now=0;
}
int main(){
    //freopen("in","r",stdin);
    int T=read();
    memset(f,-1,sizeof(f));
    while(T--){
        n=read();
        int x=0,y=0,a;
        for(int i=1;i<=n;i++){
            a=read();
            if(a==1) x++;
            else y+=a+1;
        }
        if(y) y--;
        puts(dfs(x,y) ? "YES" : "NO");
    }
}