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.
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
Sample Output
Source
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
