poj1330

简单题

View Code

   
     

    
      #include 
    
      <
    
      iostream
    
      >
    
      
#include 
    
      <
    
      cstdio
    
      >
    
      
#include 
    
      <
    
      cstdlib
    
      >
    
      
#include 
    
      <
    
      cstring
    
      >
    
      

    
      using
    
       
    
      namespace
    
       std;


    
      #define
    
       maxn 10005
    
      


    
      bool
    
       vis[maxn];

    
      int
    
       father[maxn];


    
      int
    
       main()
{
 
    
      //
    
      freopen("t.txt", "r", stdin);
    
      

    
       
    
      int
    
       t;
 scanf(
    
      "
    
      %d
    
      "
    
      , 
    
      &
    
      t);
 
    
      while
    
       (t
    
      --
    
      )
 {
 memset(father, 
    
      -
    
      1
    
      , 
    
      sizeof
    
      (father));
 memset(vis, 
    
      0
    
      , 
    
      sizeof
    
      (vis));
 
    
      int
    
       n;
 scanf(
    
      "
    
      %d
    
      "
    
      , 
    
      &
    
      n);
 
    
      int
    
       a, b;
 
    
      for
    
       (
    
      int
    
       i 
    
      =
    
       
    
      0
    
      ; i 
    
      <
    
       n 
    
      -
    
       
    
      1
    
      ; i
    
      ++
    
      )
 {
 scanf(
    
      "
    
      %d%d
    
      "
    
      , 
    
      &
    
      a, 
    
      &
    
      b);
 father[b] 
    
      =
    
       a;
 }
 scanf(
    
      "
    
      %d%d
    
      "
    
      , 
    
      &
    
      a, 
    
      &
    
      b);
 
    
      while
    
       (b 
    
      !=
    
       
    
      -
    
      1
    
      )
 {
 vis[b] 
    
      =
    
       
    
      true
    
      ;
 b 
    
      =
    
       father[b];
 }
 
    
      while
    
       (
    
      !
    
      vis[a])
 a 
    
      =
    
       father[a];
 printf(
    
      "
    
      %d\n
    
      "
    
      , a);
 }
 
    
      return
    
       
    
      0
    
      ;
}