-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathL852.java
More file actions
43 lines (38 loc) · 1.17 KB
/
L852.java
File metadata and controls
43 lines (38 loc) · 1.17 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
package com.liang.leetcode.binarySearch;
/**
* @ClassName: L852
* @Description: 山脉数组的峰顶索引
* @Author: LiaNg
* @Date: 2020/3/19 12:13
*/
public class L852 {
public static void main(String[] args) {
L852 l852 = new L852();
int[] A = new int[]{0, 2, 1, 0};
System.out.println("l852.peakIndexInMountainArray(A) = " + l852.peakIndexInMountainArray(A));
}
/**
* 我们把符合下列属性的数组 A 称作山脉：
* A.length >= 3
* 存在 0 < i < A.length - 1 使得 A[0] < A[1] < ... A[i-1] < A[i] > A[i+1] > ... > A[A.length - 1]
* 给定一个确定为山脉的数组，返回任何满足 A[0] < A[1] < ... A[i-1] < A[i] > A[i+1] > ... > A[A.length - 1] 的 i 的值。
* 提示：
* 3 <= A.length <= 10000
* 0 <= A[i] <= 10^6
* A 是如上定义的山脉
*/
public int peakIndexInMountainArray(int[] A) {
int l = 0;
int r = A.length - 1;
int m;
while (l < r) {
m = l + (r - l) / 2;
if (A[m] < A[m + 1]) {
l = m + 1;
} else {
r = m;
}
}
return l;
}
}