POJ 2425 A Chess Game#树形SG

Posted 2020-06-18 ATM

http://poj.org/problem?id=2425

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;

struct node
{
    int to,next;
}e[10000010];
int head[1010],Ecou;
int sg[1010];

void add_edge(int u,int v)
{
    e[Ecou].to=v;
    e[Ecou].next=head[u];
    head[u]=Ecou++;
}

int getsg(int n)
{
    if(sg[n]!=-1)
        return sg[n];

    bool vis[1010];
    memset(vis,0,sizeof(vis));
    for(int i=head[n];i>=0;i=e[i].next)
    {
        sg[e[i].to]=getsg(e[i].to);
        vis[sg[e[i].to]]=1;
    }
    for(int i=0;;i++)
        if(!vis[i])
            return sg[n]=i;
}

int main()
{
    int n;
    while(~scanf("%d",&n))
    {
        memset(head,-1,sizeof(head));
        Ecou=0;
        int num,a;
        for(int i=0;i<n;i++)
        {
            scanf("%d",&num);
            while(num--)
            {
                scanf("%d",&a);
                add_edge(i,a);
            }
        }
        memset(sg,-1,sizeof(sg));
        while(1)
        {
            int m,x,ans=0;
            scanf("%d",&m);
            if(!m) break;

            while(m--)
            {
                scanf("%d",&x);
                ans^=getsg(x);
            }
            if(ans) printf("WIN\n");
            else printf("LOSE\n");
        }
    }
    return 0;
}