ZOJ 3666 Alice and Bob（博弈）

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转载请注明出处，谢谢http://blog.csdn.net/ACM_cxlove?viewmode=contents by---cxlove

比较明显的树形博弈，求个SG函数就行了。

但是求后继判断是递归的，RE到死，结果是爆栈了。

改成非递归。

http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=3666

#include<iostream>#include<cstdio>#include<map>#include<cstring>#include<cmath>#include<vector>#include<algorithm>#include<set>#include<string>#include<queue>#include<stack>#define inf 100000005#define M 4005#define N 10005#define maxn 300005#define eps 1e-10#define zero(a) fabs(a)<eps#define Min(a,b) ((a)<(b)?(a):(b))#define Max(a,b) ((a)>(b)?(a):(b))#define pb(a) push_back(a)#define mp(a,b) make_pair(a,b)#define mem(a,b) memset(a,b,sizeof(a))#define LL unsigned long long#define MOD 1000000007#define lson step<<1#define rson step<<1|1#define sqr(a) ((a)*(a))#define Key_value ch[ch[root][1]][0]#pragma comment(linker, "/STACK:1024000000,1024000000")using namespace std;vector<int>e[N];int n,sg[N];struct Rec{    int v;    bool vis[M];    Rec() {}    Rec(int _v): v(_v) {mem(vis,0);}};int cur[N];int get_sg(int root){    if (sg[root]!=-1) return sg[root];    mem(cur,0);    stack<Rec> q;    q.push(Rec(root));    while (!q.empty())    {        loop:        int u=q.top().v;        sg[u]=0;        for (int& i=cur[u]; i<e[u].size(); i)        {            int v=e[u][i];            if (sg[v]==-1)            {                q.push(Rec(v));                goto loop;            }            else { q.top().vis[sg[v]]=1; i++; }        }        for (int i=0; i<M; i++) if (!q.top().vis[i])        {            sg[u]=i;            break;        }        q.pop();    }    return sg[root];}int main(){    int cas=0;   // freopen("1.in","r",stdin);    while(scanf("%d",&n)!=EOF)    {        printf("Case %d:\n",++cas);        for(int i=1;i<=n;i++) e[i].clear();        for(int i=1;i<n;i++)        {            int k,v;            scanf("%d",&k);            while(k--)            {                scanf("%d",&v);                e[i].pb(v);            }        }        mem(sg,-1);        int q;        scanf("%d",&q);        while(q--)        {            int k,v;            int ans=0;            scanf("%d",&k);            while(k--)            {                scanf("%d",&v);                ans^=get_sg(v);            }          //  for(int i=1;i<=n;i++) cout<<i<<" "<<get_sg(i)<<endl;            puts(ans?"Alice":"Bob");        }    }    return 0;}