首页 > 代码库 > HDU 5323 SOLVE THIS INTERESTING PROBLEM 爆搜

HDU 5323 SOLVE THIS INTERESTING PROBLEM 爆搜

链接

Solve this interesting problem

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 511    Accepted Submission(s): 114


Problem Description
Have you learned something about segment tree? If not, don’t worry, I will explain it for you.
Segment Tree is a kind of binary tree, it can be defined as this:
- For each node u in Segment Tree, u has two values:  and .
- If , u is a leaf node. 
- If , u has two children x and y,with ,,,.
Here is an example of segment tree to do range query of sum.

技术分享


Given two integers L and R, Your task is to find the minimum non-negative n satisfy that: A Segment Tree with root node‘s value  and contains a node u with  and .
 

Input
The input consists of several test cases. 
Each test case contains two integers L and R, as described above.


 

Output
For each test, output one line contains one integer. If there is no such n, just output -1.
 

Sample Input
6 7 10 13 10 11
 

Sample Output
7 -1 12
 

Source
2015 Multi-University Training Contest 3
 

题意:
给定区间[l,r]
用线段树的递归建树方式build(1, n)
问最小的n是多少,使得build(1,n) 中能直接建出区间[l,r]
思路:
注意一下范围,然后推算一下就能发现这个区间距离根节点的距离不超过10
所以从底向上搜就好了

代码

HDU 5323 SOLVE THIS INTERESTING PROBLEM 爆搜