Limited Time Offer:30% off Hello Interview Premium 🎉

Back to Main

Learn DSA

Introduction

Two Pointers

Overview

Container With Most Water

3-Sum

Triangle Numbers

Move Zeroes

Sort Colors

Trapping Rain Water

Sliding Window

Overview

Longest Substring Without Repeating Characters

Longest Repeating Character Replacement

Overview

Maximum Sum of Subarrays of Size K

Max Points You Can Obtain From Cards

Max Sum of Distinct Subarrays Length k

Intervals

Overview

Can Attend Meetings

Insert Interval

Non-Overlapping Intervals

Merge Intervals

Employee Free Time

Stack

Overview

Valid Parentheses

Decode String

Longest Valid Parentheses

Overview

Daily Temperatures

Largest Rectangle in Histogram

Linked List

Overview

Linked List Cycle

Palindrome Linked List

Remove Nth Node From End of List

Reorder List

Swap Nodes in Pairs

Binary Search

Overview

Apple Harvest (Koko Eating Bananas)

Search in Rotated Sorted Array

Heap

Overview

Kth Largest Element in an Array

K Closest Points to Origin

Find K Closest Elements

Merge K Sorted Lists

Breadth-First Search

Introduction

Overview

Level Order Sum

Rightmost Node

Zigzag Level Order

Maximum Width of Binary Tree

Graphs Overview

Minimum Knight Moves

Rotting Oranges

01-Matrix

Bus Routes

Backtracking

Overview

Word Search

Solution Space Trees

Subsets

Generate Parentheses

Combination Sum

Graphs

Overview

Course Schedule

Course Schedule II

Dynamic Programming

Fundamentals

Solving a Question with Dynamic Programming

Counting Bits

Decode Ways

Maximal Square

Unique Paths

Longest Increasing Subsequence

Word Break

Maximum Profit in Job Scheduling

Greedy Algorithms

Overview

Best Time to Buy and Sell Stock

Gas Station

Jump Game

Trie

Overview

Implement Trie Methods

Prefix Matching

Prefix Sum

Overview

Count Vowels in Substrings

Subarray Sum Equals K

Matrices

Spiral Matrix

Rotate Image

Set Matrix Zeroes

Pricing

Become a Coach

Pricing Become a Coach

Get Premium

Heap

Kth Largest Element in an Array

medium

DESCRIPTION (credit Leetcode.com)

Write a function that takes an array of unsorted integers nums and an integer k, and returns the kth largest element in the array. This function should run in O(n log k) time, where n is the length of the array.

Example 1:

Inputs:


nums = [5, 3, 2, 1, 4]
k = 2

Output:

Explanation

Approach 1: Sorting

The simplest approach is to sort the array in descending order and return the kth element. This approach has a time complexity of O(n log n) where n is the number of elements in the array, and a space complexity of O(1).

Approach 2: Min Heap

By using a min-heap, we can reduce the time complexity to O(n log k), where n is the number of elements in the array and k is the value of k.

The idea behind this solution is to iterate over the elements in the array while storing the k largest elements we've seen so far in a min-heap. At each element, we check if it is greater than the smallest element (the root) of the heap. If it is, we pop the smallest element from the heap and push the current element into the heap. This way, the heap will always contain the k largest elements we've seen so far.

After iterating over all the elements, the root of the heap will be the kth largest element in the array.

Solution


def kth_largest(nums, k):
    if not nums:
        return 
    
    heap = []
    for num in nums:
        if len(heap) < k:
            heapq.heappush(heap, num)
        elif num > heap[0]:
            heapq.heappushpop(heap, num)
    
    return heap[0]

kth largest element in an array

0 / 10

Test Your Knowledge

Complexity Analysis

Time Complexity: O(n log k) where n is the number of elements in the array and k is the input parameter. We iterate over all elements, and in the worst case, we both push and pop each element from the heap, which takes O(log k) time per element.

Space Complexity: O(k) where k is the input parameter. The space is used by the heap to store the k largest elements.

Next: K Closest Points to Origin

Your account is free and you can post anonymously if you choose.

Heap

Kth Largest Element in an Array

DESCRIPTION (credit Leetcode.com)

Explanation

Approach 1: Sorting

Approach 2: Min Heap

Solution

Test Your Knowledge

Complexity Analysis

Questions

Learn

Links

Legal

Contact