poj 1470 Closest Common Ancestors

http://poj.org/problem?id=1470

裸LCA：读入数据很诡异。

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<vector>
#include<algorithm>
#include<stdlib.h>
using namespace std;
const int maxn = 1000;
struct nd
{
        int to,next;
}edge[maxn*2];
vector<int>qes[maxn];
int vis[maxn],ans[maxn];
int in[maxn],f[maxn];
int ecnt,head[maxn],fa[maxn];
void add(int s,int t)
{
        edge[ecnt].to = t;
        edge[ecnt].next = head[s];
        head[s] = ecnt++;
}
int Find(int x)
{
        if(x!=f[x]) f[x] = Find(f[x]);
        return f[x];
}
void LCA(int u)
{
        int i,v,x,y;
        ans[u] = u;
        for(i = head[u]; i != -1; i = edge[i].next)
        {
                v = edge[i].to;
                LCA(v);
                x = Find(u);
                y = Find(v);
                if(x!=y) f[y] = x;
                ans[Find(u)] = u;
        }
        vis[u] = 1;
        for(i = 0; i < qes[u].size(); ++ i){
                v = qes[u][i];
                if(vis[v]) fa[ans[Find(v)]]++;
        }
}
inline bool get(int &a)
{
    char c;
    while(((c=getchar())<'0'||c>'9')&&c!=EOF);
    if(c==EOF)return 0;
    for(a=0;c>='0'&&c<='9';c=getchar())a=a*10+c-'0';
    return 1;
}
int main()
{
        int i,s,t,k,n;
        while(get(n))
        {
                memset(vis,0,sizeof(vis));
                memset(ans,0,sizeof(ans));
                memset(in,0,sizeof(in));
                memset(fa,0,sizeof(fa));
                memset(head,-1,sizeof(head));
                for(i = 0; i <= n; ++ i) qes[i].clear();
                for(i = 0; i <= n; ++ i) f[i] = i;

                ecnt = 0;
                for(i = 1; i <= n; ++ i)
                {
                        get(s); get(k);
                        while(k--)
                        {
                                get(t);
                                add(s,t);
                                in[t]++;
                        }
                }
                get(k);
                while(k--)
                {
                        get(s); get(t);
                        if(s==t){ fa[s]++; continue;}
                        qes[s].push_back(t);
                        qes[t].push_back(s);
                }
                for(i = 1; i <= n; ++ i) if(!in[i])break;
                LCA(i);
                for(i = 1; i <= n; ++ i) if(fa[i]) printf("%d:%d\n",i,fa[i]);
        }return 0;
}