二叉树 小球下落问题

#include <stdio.h>
#include <string.h>
#define MAXD 20
int state[1<<MAXD];
int main()
{
    int D, I;
    while(scanf("%d%d", &D, &I) == 2)
    {
        int i, k, n = (1<<D)-1;
        memset(state, 0, sizeof(state));
        for(i = 0; i < I; i++)
        {
            for(k = 1;;)
            {
                state[k] = !state[k];
                k = state[k] ? (2*k) : (2*k+1);
                if(k > n)    break;
            }
        }
        printf("%d\n", k/2);
    }
    return 0;
}

#include <stdio.h>
int main()
{
    int D, I;
    while(scanf("%d%d", &D, &I) == 2)
    {
        int i, k = 1;
        for(i = 0; i < D - 1; i++)
        {
            if(I % 2 == 1)
            {
                k = k * 2;
                I = (I + 1)/2; //左子树比右子树多落一个
            }
            else
            {
                k = k * 2 + 1;
                I = I / 2;
            }
        }
        printf("%d\n", k);
    }
    return 0;
}