1312.txt

来自「自己AC的zju_acm上的若干个题目,都是自己辛辛苦苦AC的。」· 文本 代码 · 共 60 行

#include <iostream> 
using namespace std; 

typedef unsigned long ulong; 

int get_primes(ulong limit, ulong *primes)       

{ 
   int count = 1; 
   ulong i; 

   primes[0] = 1; 
   if (limit == 1) 
      return 1; 

     primes[1] = 2; 
     ++count; 
   if (limit == 2) 
      return 2; 

   for (i = 3; i <= limit; i += 2) 
   { 
      int k; 
      for (k = 1; k < count; k++) 
         if ( i%primes[k] == 0 ) 
            break; 
      if ( k == count ) 
      { 
         primes[count++] = i; 
      } 
    } 
     return count;    
} 

int main() 
{ 
   ulong limit, c; 
   while (cin >> limit >> c) 
    { 
       int count, i, start; 
       ulong *primes = new ulong[limit]; 
        count = get_primes(limit, primes); 
    
        cout << limit << " " << c << ":"; 
          if (count/2 < c)    
        { 
           start = 0; 
           c = count/2 + count%2; 
          } 
          else 
             start = count/2 - c + count%2; 
          for (i = start; i < start + 2*c- count%2; i++) 
             cout << " " << primes[i]; 

        cout << endl << endl; 
       delete [] primes; 
     }    
    return 0; 
}