Poj1470 Closest Common Ancestors LCA

　　LCA裸题。。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<map>
#include<vector>
using namespace std;
const int maxn = 1111;
int head[maxn];
int len;
struct Node
{
    int to; int next;
}e[maxn * 2];
int father[maxn];
int color[maxn];
int vis[maxn];
int gg[maxn];
vector <int> q[maxn];
void add(int from, int to)
{
    e[len].to = to;
    e[len].next = head[from];
    head[from] = len++;
}

int getfather(int x)
{
    if (father[x] != x) father[x] = getfather(father[x]);
    return father[x];
}

void un(int a, int b)
{
    int fa = getfather(a); int fb = getfather(b);
    father[fb] = fa;
}


void dfs(int x)
{
    for (int i = head[x]; ~i; i = e[i].next){
        int cc = e[i].to;
        dfs(cc);
        un(x, cc);
    }
    color[x] = 1;
    for (int i = 0; i <q[x].size(); i++){
        int t = q[x][i];
        if (color[t]){
            int t1 = getfather(q[x][i]);
            vis[t1]++;
        }
    }
}

void init(int n)
{
    len = 0;
    memset(head, -1, sizeof(head));
    for (int i = 1; i <= n; i++)
        father[i] = i;
    memset(head, -1, sizeof(head));
    for (int i = 1; i <= n; i++)
        q[i].clear();
    memset(color, 0, sizeof(color));
    for (int i = 1; i <= n; i++)
        vis[i] = 0;
    for (int i = 1; i <= n; i++)
        gg[i] = 0;
}


int main()
{
    int n;
    while (cin >> n){
        init(n);
        int m, a, b, c;
        for (int i = 0; i<n; i++){
            scanf("%d", &a);
            scanf(":(%d)", &b);
            for (int j = 0; j<b; j++){
                scanf("%d", &c);
                add(a, c);
                gg[c] = 1;
            }
        }
        scanf("%d", &m);
        while (m--){
            scanf(" (%d %d)", &a, &b);
            //  printf("%d %djiji
",a,b);
            q[a].push_back(b);
            q[b].push_back(a);
        }
        int root;
        for (int i = 1; i <= n; i++) if (!gg[i]){
            root = i; break;
        }
        dfs(root);
        for (int i = 1; i <= n; i++){
            if (vis[i]){
                printf("%d:%d
", i, vis[i]);
            }
        }
    }
    return 0;
}