162. Find Peak Element
A peak element is an element that is greater than its neighbors.
Given an input array nums, where nums[i] ≠ nums[i+1], find a peak element and return its index.
The array may contain multiple peaks, in that case return the index to any one of the peaks is fine.
You may imagine that nums[-1] = nums[n] = -∞.
Example 1:
Input: nums = [1,2,3,1] Output: 2 Explanation: 3 is a peak element and your function should return the index number 2.
Example 2:
Input: nums = [1,2,1,3,5,6,4] Output: 1 or 5 Explanation: Your function can return either index number 1 where the peak element is 2, or index number 5 where the peak element is 6.
Note:
Your solution should be in logarithmic complexity.
题意：给定一个相邻项不相等的数字数组，求峰值的索引
参考：https://leetcode-cn.com/problems/two-sum/solution/xun-zhao-feng-zhi-by-leetcode/
代码如下：
/**
* @param {number[]} nums
* @return {number}
*/
// 因为nums[i-1]不等于nums[i] 并且两头都是负无穷大 所以一定会有峰值存在
// 所以从前往后遍历的过程中只要刚出现nums[i]>nums[i+1] nums[i]就是峰值
var findPeakElement = function(nums) {
for(let i=0;i<nums.length;i++){
if(nums[i]>nums[i+1]){
return i;
}
}
return nums.length-1;
};