方法三:迭代二分查找
public int findPeakElement(int[] nums) { //第二种方法不用左右加个边界 return helper(nums, 0, nums.length-1); } public int helper(int[] nums, int left, int right){ while(left<right){ //这没有== int mid = (left+right)/2; if(nums[mid]<nums[mid+1]){ left = mid+1; }else{ right = mid; //这没有-1 } } return left; }