hdu 2545 求当前结点到根节点的距离

求当前结点到根节点的距离

Sample Input
2 1 //n m
1 2
1 2 //询问

5 2
1 2
1 3
3 4
3 5
4 2 //询问
4 5
0 0

Sample Output
lxh
pfz
lxh

 # include <iostream>
 # include <cstdio>
 # include <cstring>
 # include <algorithm>
 # include <cmath>
 # include <queue>
 # define LL long long
 using namespace std ;

 const int MAXN = ;
 int F[MAXN];
 int dist[MAXN] ;

 int find(int x)//找x的祖先结点
 {
     if(F[x]==x) return x;
     int t = F[x] ;
     F[x]=find(F[x]);
     dist[x] += dist[t] ;
     return F[x] ;
 }

 int main()
 {
     //freopen("in.txt","r",stdin) ;
     int n , m ;
     while(scanf("%d %d", &n , &m) != EOF)
     {
          if (n ==  && m == )
              break ;
          int u , v ;
          int i ;
          for(i =  ; i <= n ; i++)
          {
              F[i] = i ;
              dist[i] =  ;
          }
          for(i =  ; i < n ; i++)
          {
              scanf("%d %d" , &u , &v) ;
              F[v] = u ;
              dist[v] =  ;
          }

         while(m--)
         {
             scanf("%d %d" , &u , &v) ;
             find(u) ;
             find(v) ;
             if (dist[u] <= dist[v])
                 printf("lxh\n") ;
             else
                 printf("pfz\n") ;
         }

     }
     return ;
 }