In this post, we are going to solve the 162. Find Peak Element problem of Leetcode. This problem 162. Find Peak Element is a Leetcode medium level problem. Let’s see the code, 162. Find Peak Element – Leetcode Solution.
Problem
A peak element is an element that is strictly greater than its neighbors.
Given a 0-indexed integer array nums
, find a peak element, and return its index. If the array contains multiple peaks, return the index to any of the peaks.
You may imagine that nums[-1] = nums[n] = -∞
. In other words, an element is always considered to be strictly greater than a neighbor that is outside the array.
You must write an algorithm that runs in O(log n)
time.
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: 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.
Constraints
1 <= nums.length <= 1000
-231 <= nums[i] <= 231 - 1
nums[i] != nums[i + 1]
for all validi
.
Now, let’s see the code of 162. Find Peak Element – Leetcode Solution.
Find Peak Element – Leetcode Solution
162. Find Peak Element – Solution in Java
class Solution { public int findPeakElement(int[] nums) { int s = 0; int e = nums.length-1; while(s < e){ int mid = s - ( s - e)/2; int mid2 = mid+1; if(nums[mid] < nums[mid2]) { s = mid2; }else { e = mid; } } return s; } }
162. Find Peak Element – Solution in C++
class Solution { public: int findPeakElement(vector<int>& nums) { int s = 0; int e = nums.size()-1; while(s < e){ int mid = s - ( s - e)/2; int mid2 = mid+1; if(nums[mid] < nums[mid2]) { s = mid2; }else { e = mid; } } return s; } };
162. Find Peak Element – Solution in Python
class Solution: def findPeakElement(self, nums): beg, end = 0, len(nums) - 1 while beg < end: mid = (beg + end)//2 if nums[mid] < nums[mid + 1]: beg = mid + 1 else: end = mid return end
Note: This problem 162. Find Peak Element is generated by Leetcode but the solution is provided by CodingBroz. This tutorial is only for Educational and Learning purpose.