poj3100

本来想到二分查找，后来发现直接使用pow,floor和ceil就可以。这些函数在cmath中。

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

    
      using
    
       
    
      namespace
    
       std;


    
      int
    
       main()
{
 freopen(
    
      "
    
      D:\\t.txt
    
      "
    
      , 
    
      "
    
      r
    
      "
    
      , stdin);
 
    
      int
    
       b, n;
 
    
      while
    
       (scanf(
    
      "
    
      %d%d
    
      "
    
      , 
    
      &
    
      b, 
    
      &
    
      n) 
    
      !=
    
       EOF 
    
      &&
    
       
    
      !
    
      (b 
    
      ==
    
       
    
      0
    
       
    
      &&
    
       n 
    
      ==
    
       
    
      0
    
      ))
 {
 
    
      double
    
       a 
    
      =
    
       pow(b, 
    
      1.0
    
       
    
      /
    
       n);
 
    
      int
    
       a1, a2;
 a1 
    
      =
    
       (
    
      int
    
      ) floor(a);
 a2 
    
      =
    
       (
    
      int
    
      ) ceil(a);
 
    
      int
    
       d1 
    
      =
    
       abs((
    
      int
    
      ) pow((
    
      double
    
      ) a1, n) 
    
      -
    
       b);
 
    
      int
    
       d2 
    
      =
    
       abs((
    
      int
    
      ) pow((
    
      double
    
      ) a2, n) 
    
      -
    
       b);
 
    
      if
    
       (d1 
    
      >
    
       d2)
 printf(
    
      "
    
      %d\n
    
      "
    
      , a2);
 
    
      else
    
      
 printf(
    
      "
    
      %d\n
    
      "
    
      , a1);
 }
 
    
      return
    
       
    
      0
    
      ;
}