我还以为要定义树的数据结构
二叉树
https://www.nowcoder.com/practice/f74c7506538b44399f2849eba2f050b5
#include <stdio.h> int func(int m,int n){ if(m>n)return 0; return func(2*m,n)+func(2*m+1,n)+1; } int main(){ int m,n; while(scanf("%d%d",&m,&n)!=EOF){ printf("%d\n",func(m,n)); } return 0; }