二叉树 （C语言代码）

#include <stdio.h>

#include <stdlib.h>

#include <math.h>

int main(){

    int left, right, m, n, k, sum;

    while(scanf("%d %d", &m, &n) != EOF && m != 0 && n != 0){

         left = right = m;

         k = 1;

         while(2 * right + 1 <= n){

             right = 2 * right + 1;

             left *= 2;

             ++k;

         }

         sum = pow(2, k) - 1;

         if(2 * left <= n) sum += n - 2 * left + 1;

              printf("%d\n", sum);

     };

     return 0;

}