nyist oj 63(二叉树)

题目链接：http://acm.nyist.net/JudgeOnline/problem.php?pid=63

代码如下：

#include <cstdio>
#include <cstring>
using namespace std;

const int N = 20;
int s[1 << N];

int main()
{
    int d, r;
    while(scanf("%d%d", &d, &r) != EOF)
    {
            memset(s, 0, sizeof(s));
            int k, n = (1 << d)-1;
            for(int j = 0; j < r; j++)
            {
                    k = 1; 
                    for(; ;)
                    {
                          s[k] = !s[k];
                          k = s[k] ? k*2 : k*2+1;
                          if(k > n)
                               break;      
                    }        
            }                    
            printf("%d\n", k / 2);
    }
    return 0;    
}

更精简的代码如下：

#include <cstdio>
using namespace std;

int main()
{
    int d, r;
    while(scanf("%d%d", &d, &r) != EOF)
    {
         int k = 1;
         for(int i = 0; i < d-1; i++)
         {
                 if(r % 2)
                 {
                      k = k*2;
                      r = (r+1)/2;     
                 }              
                 else
                 {
                      k = k*2+1;
                      r /= 2;    
                 }
         }   
         printf("%d\n", k);                
    }
    return 0;    
}