Full Binary Tree

Time Limit: 2000MS Memory limit: 65536K

题目描述

In computer science, a binary tree is a tree data structure in which each node has at most two children. Consider an infinite full binary tree (each node has two children except the leaf nodes) defined as follows. For a node labelled v its left child will be labelled 2 * v and its right child will be labelled 2 * v + 1. The root is labelled as 1.

You are given n queries of the form i, j. For each query, you have to print the length of the shortest path between node labelled i and node labelled j.

输入

First line contains n(1 ≤ n ≤ 10^5), the number of queries. Each query consists of two space separated integers i and j(1 ≤ i, j ≤ 10^9) in one line.

输出

For each query, print the required answer in one line.

示例输入

5

1 2

2 3

4 3

1024 2048

3214567 9998877

示例输出

1

2

3

1

44

来源

2014年山东省第五届ACM大学生程序设计竞赛

题意：

已知满二叉树，根节点编号为1，节点v的左右孩子编号依次为2*v、2*v+1,求从某一节点到另一节点之间的路径长度，例如从4到3路径为4–>2–>1–>3,需要3步，，，

思路：

从较大的节点开始不断的往上找，节点编号除以2便是他的父节点，每找一次每走一步路径加一，直到两个节点编号相同，，，

以下AC代码：

#include <stdio.h>  
int main()  
{  
    int i,j;  
    int n,m;  
    int T;  
    scanf("%d",&T);  
    while(T--)  
    {  
        int count=0;  
        scanf("%d %d",&n,&m);  
        while(n!=m)  
        {  
            if(n>m)  
                n/=2;  
            else  
                m/=2;  
            count++;  
        }  
        printf("%d\n",count);  
    }  
      
    return 0;  
}