poj1306

简单题

View Code

   
     

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

    
      using
    
       
    
      namespace
    
       std;


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


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

    
       
    
      long
    
       
    
      long
    
       m, n;
 
    
      while
    
       (scanf(
    
      "
    
      %lld%lld
    
      "
    
      , 
    
      &
    
      m, 
    
      &
    
      n), m 
    
      |
    
       n)
 printf(
    
      "
    
      %lld things taken %lld at a time is %lld exactly.\n
    
      "
    
      , m, n, com(m, n));
 
    
      return
    
       
    
      0
    
      ;
}