Peak Index in a Mountain Array
Let's call an array A a mountain if the following properties hold: A.length >= 3 There exists some 0 < i < A.length - 1 such that A[0] < A[1] < ... A[i-1] < A[i] > A[i+1] > ... > A[A.length - 1] Given an array that is definitely a mountain, return any i such that A[0] < A[1] < ... A[i-1] < A[i] > A[i+1] > ... > A[A.length - 1] . Example 1: Input: [0,1,0] Output: 1 Example 2: Input: [0,2,1,0] Output: 1 思路:就是binary search;mid跟mid+1比较; class Solution { public int peakIndexInMountainArray(int[] A) { if(A == null || A.length == 0) { return 0; } int start = 0; int end = A.length - 1; while(start + 1