2591.txt

北大ACM题目例程 详细的解答过程 程序实现 算法分析

Problem Id:2591  User Id:fzk 
Memory:39168K  Time:249MS
Language:C++  Result:Accepted

Source 

#include "stdio.h"

int a[10000000];

int main()
{
    int i, j, k, tj, tk;
    
    a[0]=1;
    for( j=0,k=0,i=1; i<10000000; i++ )
    {
        if( ( tj = a[j]*2+1 ) < ( tk = a[k]*3+1 ) )
                a[i] = tj, j++;
        else if( tj > tk )
                a[i] = tk, k++;
        else  a[i] = tk, j++, k++;
     }
     
     while( scanf( "%d", &i ) == 1 )
     {
       printf( "%d\n", a[i-1] );
     }
     
     return 0;
}