852. 山脉数组的峰顶索引

题目链接：https://leetcode.cn/problems/peak-index-in-a-mountain-array/description/

Java

class Solution {
    public int peakIndexInMountainArray(int[] arr) {
        int high = arr.length - 1;
        int low = 0;
        int mid = 0;
        while (low < high) {
            mid = low  + ((high - low) / 2);
            int midVal = arr[mid];
            if (midVal > arr[mid-1] && midVal > arr[mid+1]) {
                break;
            }
            if (midVal > arr[mid+1]) {
                high = mid;
            } else {
                low = mid;
            }
        }
        return mid;
    }
}