poj1775

搜索，注意0是NO

View Code

   
     

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

    
      using
    
       
    
      namespace
    
       std;


    
      int
    
       fac[
    
      20
    
      ];

    
      bool
    
       f[
    
      1000005
    
      ];

    
      int
    
       tot;


    
      void
    
       dfs(
    
      int
    
       i, 
    
      int
    
       sum)
{
 
    
      if
    
       (sum 
    
      >
    
       
    
      1000000
    
      )
 
    
      return
    
      ;
 f[sum] 
    
      =
    
       
    
      true
    
      ;
 
    
      if
    
       (i 
    
      ==
    
       tot)
 
    
      return
    
      ;
 dfs(i 
    
      +
    
       
    
      1
    
      , sum 
    
      +
    
       fac[i]);
 dfs(i 
    
      +
    
       
    
      1
    
      , sum);
}


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

    
       fac[
    
      0
    
      ] 
    
      =
    
       
    
      1
    
      ;
 tot 
    
      =
    
       
    
      0
    
      ;
 
    
      for
    
       (
    
      int
    
       i 
    
      =
    
       
    
      1
    
      ; fac[i 
    
      -
    
       
    
      1
    
      ] 
    
      <=
    
       
    
      1000000
    
      ; i
    
      ++
    
      )
 {
 fac[i] 
    
      =
    
       fac[i 
    
      -
    
       
    
      1
    
      ] 
    
      *
    
       i;
 tot
    
      ++
    
      ;
 }
 memset(f, 
    
      0
    
      , 
    
      sizeof
    
      (f));
 dfs(
    
      0
    
      , 
    
      0
    
      );
 
    
      int
    
       n;
 
    
      while
    
       (scanf(
    
      "
    
      %d
    
      "
    
      , 
    
      &
    
      n), n 
    
      >=
    
       
    
      0
    
      )
 
    
      if
    
       (f[n] 
    
      &&
    
       n 
    
      !=
    
       
    
      0
    
      )
 printf(
    
      "
    
      YES\n
    
      "
    
      );
 
    
      else
    
      
 printf(
    
      "
    
      NO\n
    
      "
    
      );
 
    
      return
    
       
    
      0
    
      ;
}