Goldbach's Conjecture--POJ 2262

1、题目类型：数论。

2、解题思路：水题。

3、实现方法:

  
    

   
     
   
     #include
   
     <
   
     iostream
   
     >
   
     
#include
   
     <
   
     map
   
     >
   
     

   
     using
   
      
   
     namespace
   
      std;


   
     bool
   
      prime[
   
     1000000
   
     ];


   
     void
   
      BuildTable()
{
 
   
     int
   
      i,j;
 prime[
   
     1
   
     ]
   
     =
   
     prime[
   
     2
   
     ]
   
     =
   
     false
   
     ;
 
   
     for
   
     (i
   
     =
   
     2
   
     ;i
   
     <
   
     1000
   
     ;i
   
     ++
   
     )
 {
 
   
     for
   
     (j
   
     =
   
     2
   
     ;j
   
     *
   
     i
   
     <
   
     1000000
   
     ;j
   
     ++
   
     )
 {
 prime[j
   
     *
   
     i]
   
     =
   
     false
   
     ;
 }
 }
}


   
     int
   
      main()
{
 
   
     int
   
      i,n;
 memset(prime,
   
     1
   
     ,
   
     sizeof
   
     (prime));
 BuildTable();
 
   
     while
   
     (cin
   
     >>
   
     n 
   
     &&
   
      n)
 {
 
   
     for
   
     (i
   
     =
   
     1
   
     ;i
   
     <=
   
     n
   
     /
   
     2
   
     ;i
   
     ++
   
     )
 {
 
   
     if
   
     (prime[i] 
   
     &&
   
      prime[n
   
     -
   
     i])
 {
 cout
   
     <<
   
     n
   
     <<
   
     "
   
      = 
   
     "
   
     <<
   
     i
   
     <<
   
     "
   
      + 
   
     "
   
     <<
   
     n
   
     -
   
     i
   
     <<
   
     endl;
 
   
     break
   
     ;
 }
 }
 }
 
   
     return
   
      
   
     1
   
     ;
}