poj2081

简单题

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

    
      using
    
       
    
      namespace
    
       std;


    
      #define
    
       maxn 500004
    
      


    
      int
    
       f[maxn];

    
      bool
    
       vis[maxn 
    
      *
    
       
    
      10
    
      ];


    
      int
    
       main()
{

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

    
       memset(vis, 
    
      0
    
      , 
    
      sizeof
    
      (vis));
 f[
    
      0
    
      ] 
    
      =
    
       
    
      0
    
      ;
 
    
      for
    
       (
    
      int
    
       i 
    
      =
    
       
    
      1
    
      ; i 
    
      <
    
       maxn; i
    
      ++
    
      )
 {
 f[i] 
    
      =
    
       f[i 
    
      -
    
       
    
      1
    
      ] 
    
      -
    
       i 
    
      >
    
       
    
      0
    
       
    
      &&
    
       
    
      !
    
      vis[f[i 
    
      -
    
       
    
      1
    
      ] 
    
      -
    
       i]
    
      ?
    
       f[i 
    
      -
    
       
    
      1
    
      ] 
    
      -
    
       i : f[i 
    
      -
    
       
    
      1
    
      ] 
    
      +
    
       i;
 vis[f[i]] 
    
      =
    
       
    
      true
    
      ;
 }
 
    
      int
    
       n;
 
    
      while
    
       (scanf(
    
      "
    
      %d
    
      "
    
      , 
    
      &
    
      n), n 
    
      !=
    
       
    
      -
    
      1
    
      )
 printf(
    
      "
    
      %d\n
    
      "
    
      , f[n]);
 
    
      return
    
       
    
      0
    
      ;
}