CF1110G Tree-Tac-Toe（博弈论）

一时失言乱红尘 2021-12-23 05:43 266阅读 0赞

## 题面 ##

[传送门][Link 1]

## 题解 ##

博弈论的前提是双方都是绝顶聪明的人

所以这种题目显然不是我应该做的

[题解][Link 2]

//minamoto
    #include<bits/stdc++.h>
    #define R register
    #define fp(i,a,b) for(R int i=(a),I=(b)+1;i<I;++i)
    #define fd(i,a,b) for(R int i=(a),I=(b)-1;i>I;--i)
    #define go(u) for(int i=head[u],v=e[i].v;i;i=e[i].nx,v=e[i].v)
    using namespace std;
    char buf[1<<21],*p1=buf,*p2=buf;
    inline char getc(){return p1==p2&&(p2=(p1=buf)+fread(buf,1,1<<21,stdin),p1==p2)?EOF:*p1++;}
    int read(){
        R int res,f=1;R char ch;
        while((ch=getc())>'9'||ch<'0')(ch=='-')&&(f=-1);
        for(res=ch-'0';(ch=getc())>='0'&&ch<='9';res=res*10+ch-'0');
        return res*f;
    }
    int read(char *s){
        R int len=0;R char ch;while(((ch=getc())>'Z'||ch<'A'));
        for(s[++len]=ch;(ch=getc())>='A'&&ch<='Z';s[++len]=ch);
        return s[len+1]='\0',len;
    }
    const int N=1e6+5;
    struct eg{int v,nx;}e[N<<1];int head[N],deg[N],tot;
    inline void add(R int u,R int v){e[++tot]={v,head[u]},head[u]=tot,++deg[v];}
    char s[N];int n;
    void solve(){
        n=read(),tot=0;
        memset(head,0,4*(n+1)),memset(deg,0,4*(n+1));
        for(R int i=1,u,v;i<n;++i)u=read(),v=read(),add(u,v),add(v,u);
        read(s);
        if(n<3)return puts("Draw"),void();
        if(n==3){
            int cnt=(s[1]=='W')+(s[2]=='W')+(s[3]=='W');
            puts(cnt>1?"White":"Draw");
            return;
        }
        fp(i,1,n)if(s[i]=='W')head[++n]=0,add(i,n),add(n,i),deg[n]=3;
        int cc=0;
        fp(u,1,n)if(deg[u]>3)return puts("White"),void();
        else if(deg[u]==3){
            int cnt=0;
            go(u)cnt+=deg[v]>=2;
            if(cnt>=2)return puts("White"),void();
            ++cc;
        }
        puts((cc==2&&(n&1))?"White":"Draw");
    }
    int main(){
    //  freopen("testdata.in","r",stdin);
        int T=read();
        while(T--)solve();
        return 0;
    }

转载于:https://www.cnblogs.com/bztMinamoto/p/10650237.html

[Link 1]: http://codeforces.com/contest/1110/problem/G
[Link 2]: https://www.cnblogs.com/Itst/p/10356243.html