[leetcode] problem 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

No.1

Input: nums = [1,2,3,1]

Output: 2

Explanation: 3 is a peak element and your function should return the index number 2.

No.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.

Code

public int (int[] nums) {
    int left = 0;
    int right = nums.length - 1;

    while (left < right) {
        int mid = left + (right - left) / 2;

        if (nums[mid] > nums[mid + 1])
            right = mid;
        else
            left = mid + 1;
    }

    return right;
}

[leetcode] problem 162 – find peak element

Example

No.1

No.2

Note

Code

近期文章

近期评论

标签

热门

文章归档

分类目录

功能