题解 | 二叉树

#include <iostream>
#include <queue>
using namespace std;

int main() {
    int n, m;
    while(cin >> m >> n){
        queue<int> q;
        q.push(m);

        int sum=1;
        do{
            int temp = q.front();
            q.pop();
            int lchild = temp*2;
            int rchild = temp*2 + 1;
            if(lchild <= n){
                q.push(lchild);
                sum++;
            }
            if(rchild <= n){
                q.push(rchild);
                sum++;
            }
        }while(!q.empty());
        cout << sum << endl;
    }
}