poj2249

简单题

View Code

   
     

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

    
      using
    
       
    
      namespace
    
       std;


    
      int
    
       com(
    
      int
    
       n, 
    
      int
    
       r)
{
 
    
      if
    
       (n 
    
      -
    
       r 
    
      <
    
       r)
 r 
    
      =
    
       n 
    
      -
    
       r;
 
    
      int
    
       i , j;
 
    
      long
    
       
    
      long
    
       s 
    
      =
    
       
    
      1
    
      ;
 
    
      for
    
       (i 
    
      =
    
       
    
      0
    
      , j 
    
      =
    
       
    
      1
    
      ; i 
    
      <
    
       r; i
    
      ++
    
      )
 {
 s 
    
      *=
    
      (n 
    
      -
    
       i);
 
    
      for
    
       (; j 
    
      <=
    
       r 
    
      &&
    
       s 
    
      %
    
       j 
    
      ==
    
       
    
      0
    
      ; j
    
      ++
    
      )
 s 
    
      /=
    
       j;
 }
 
    
      return
    
       (
    
      int
    
      )s;
}


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

    
       
    
      int
    
       n, k;
 
    
      while
    
       (scanf(
    
      "
    
      %d%d
    
      "
    
      , 
    
      &
    
      n, 
    
      &
    
      k), n 
    
      |
    
       k)
 printf(
    
      "
    
      %d\n
    
      "
    
      , com(n, k));
 
    
      return
    
       
    
      0
    
      ;
}