Top k frequent elements bucket sort Thus, the inner loop will run at most k times, total, regardless of how many times the outer loop is running. Traverse the buckets from high to low to collect the top k frequent elements. Count frequency Buc leetcode, coding interview question, data structures, data structures and algorithms, faang May 1, 2024 · So you are interested in the fascinating LeetCode problem of finding the k most frequent elements in an array, the Top K Frequent Elements LeetCode problem. Top K Frequent Elements Table of contents Description Solutions Solution 1: Hash Table + Priority Queue (Min Heap) Oct 22, 2017 · Given a non-empty array of integers, return the k most frequent elements. Here are the following steps to solve this problem. gg/ddjKRXPqtk🐮 S Nov 8, 2024 · Select Top K Elements: Finally, select the top k elements from the sorted list. This would be an O (nlogn) solution. Master the "Top K Frequent Elements" problem (LeetCode 347) using *Heap**, **Bucket Sort**, and **HashMap* — all explained with clarity and depth! This problem is a frequent favorite in Leetcode 347. … In this video, we tackle one of the most frequently asked coding interview problems: Top K Frequent Elements. Retrieve Top k Elements: Start from the bucket with the highest frequency and work downward. Explore this problem and others in our library of interview replays. In addition, most_frequent does not reset every time the outer loop increments by 1. length; Also, 0 for 0 frequency case. This step is streamlined by the descending order of counts in the map. Intuitions, example walk through, and complexity analysis. Top K Frequent Elements (Amazon) Watch someone solve the top k frequent elements problem in an interview with an Amazon engineer and see the feedback their interviewer left them. These buckets are formed by uniformly distributing the elements. My idea is to sort the count map by values (the frequencies) in reverse order to keep the most frequent elements in front, then get only the keys (the numbers), and slice it until k: 🚀 https://neetcode. Top K Frequent Elements Tagged: Array, Hash Table, Divide and Conquer, Sorting, Priority Queue, Heap, Bucket Sort, Counting, Quickselect Problem # Given an array of integer and integer K, our task is to find the K most frequent elements in the Array. com/spreadsheets/d/1QNSEok-WD4LCPTrZlqq5VVTX0NbXQf27WUjkGi3aBu0/edit?usp=sharingQuestions in Mandarin: https://docs Dec 5, 2024 · Given an integer array nums, return the k most frequent elements. For this, we can use HashMap to store the number and its count. Excited to share my new Medium article on solving LeetCode 347: Top K Frequent Elements 🎯 In this write-up, I break down two popular approaches — Heap (O (n log k)) and Bucket Sort (O (n Count frequencies with HashMap, use min-heap of size k to track top k elements. For example, Given [1,1,1,2,2,3] and k = 2, return [1,2]. Once the elements are divided into buckets, they can be sorted using any other sorting algorithm. The hash map freq associates each element in nums with its count. Contribute to MAZHARMIK/Interview_DS_Algo development by creating an account on GitHub. Top K Frequent Elements Approach 1: Heap Time: O (n log k) O (n\log k) O(nlogk) Space: O (n) O (n) O(n) View xzaxz's solution of Top K Frequent Elements on LeetCode, the world's largest programming community. We can use any sorting algorithm here or even perform another bucket sort, placing each old bucket into new buckets based on frequency. Top K Frequent Elements - Explanation Problem Link Description A string can be shortened by replacing any number of non-adjacent, non-empty substrings with their lengths (without leading zeros). Wiggle Sort 75. 👨🏻💻 Day 5 — NeetCode75 | Top K Frequent Elements (Bucket Sort) Instead of sorting the elements by frequency, I sorted the frequencies themselves. This takes a time complexity of O (nlogn) (Sorting takes place in O (nlogn) , storing the frequencies in map takes O (n)) In total O (nlogn). Group numbers by their frequency into a bucket array. Aug 13, 2025 · The Top K Frequent Elements problem asks us to find the k elements that appear most frequently in a given array. Can you solve this real interview question? Top K Frequent Elements - Given an integer array nums and an integer k, return the k most frequent elements. Sep 14, 2022 · Sort the map according to the highest frequency. i) To find the most frequent elements, First, we need to know the number and its count. Oct 26, 2024 · Here’s an updated structured script that includes the Quickselect approach for solving the Top K Frequent Elements problem, along with sorting, heap, and bucket sort methods. Idea: Consider using a heap (priority queue) data structure. zero to one : foundational engineering paradigm >concept : Top k frequent element > what i think is : this is truly a good problem to understand the sorting or hash usages , what problem says Find the solution of Top K Frequent Elements Leetcode question with step by step explanation in 3 approaches and 3 solutions in languages like Java, Python, CPP. This problem is not only intriguing but also offers multiple approaches for solving it efficiently. The Can you solve this real interview question? Top K Frequent Elements - Given an integer array nums and an integer k, return the k most frequent elements. Since we need to return the k most frequent elements, we need to do a bit more work. Jan 12, 2025 · Discover three efficient approaches to solve LeetCode 347 Top K Frequent Elements problem. Sort Colors Binary Search 278. 39K subscribers Subscribed Array Bucket Sort Counting Divide and Conquer Hash Table Heap (Priority Queue) Quickselect Sorting 347. Finally, the sorted elements are gathered together in an ordered fashion. Steps: Count frequencies using a Map. Count how many times each number appears Use bucket Jun 10, 2024 · Continue to help good content that is interesting, well-researched, and useful, rise to the top! To gain full voting privileges, Source — “Working of Bucket Sort” Bucket sort works by creating an array of “buckets”, which are lists of numbers within a frequency range. Though this solution is Jun 30, 2024 · Now that all the unique elements are sorted based on frequency, we can start at the end of the frequencies array (ie. Something like this So the values are put into "buckets" which represents how often they appeared. To find the top k elements, simply take the first k elements from the sorted list. Why this works: Frequency count: O(n) Bucket sort step: O(n) Collecting top k elements: at most O(n) Given an integer array and an integer k, find the k most frequent elements in the array. Your algorithm’s time complexity must be better than O (n log n), where n is the array’s size. com/neetcode1🥷 Discord: https://discord. Search in Rotated Sorted Array 81. "Friend: "Sure, I'll use a HashMap to count frequencies, then a min heap of size k to get the top k elements. Nov 27, 2022 · I'm working on understanding a standard solution for a problem with the following name: Top K Frequent Elements where we are expected to return a resultant array of the Top K frequent elements. Jun 18, 2024 · Finding the top ( k ) most frequent elements in an array is a common question in coding interviews and a useful task in various applications like data analysis and natural language processing. Wood Cut 33. Bucket Sort: Elements with the same frequency are grouped into buckets (e. Find Minimum Apr 13, 2025 · The hash map freq associates each element in nums with its count. Create a multi-storage bucket with (maximum frequency + 1)as its size. Jan 26, 2025 · Top K Frequent Elements” presents us with an integer array and an integer k, with the goal of identifying the k most frequently occurring elements in the array. A complexity analysis on this gives O (N+K) -- N for Nov 11, 2016 · Selecting Top Frequencies: Traverse the second map to extract the k most frequent elements. The K most frequent elements can be in any order. Optimized LeetCode solution with Python, Java, C++, JavaScript, and C# code examples. Use bucket sort to achieve linear time complexity by grouping numbers by their frequency. Problem Overview The problem can be summarized as One of my friends recently interviewed at Info Edge,Interviewer: "Find the k most frequent elements in an array. Often times, I am thinking about using the least amount of resources as possible, and I usually run into a dead end doing so. We’ll first solve it using a min heap to maintain the top K elements, and then show Now, how do I more efficiently find top k elements without sorting' to ' I should use a bucket array!' This has been a common problem for me so far when doing leetcode problems where I feel as if I’m missing the intuition or logical thought process to solving these problems efficiently. Custom Sort String 347. Top K Frequent Elements | Bucket Sort | C++ | Hindi | Abhishek SenseiConnect With Me On: → G 00:00 algorithm process01:43 code walkthrough This video explains a very important programming interview problem which is to find the top k frequent elements in a given array. The frequency of an element is defined as the number of times it appears in the array, and the result can be returned in any order. TC:O (n) SC:O (n) solution in Java using bucket sort Can you solve this real interview question? Top K Frequent Elements - Given an integer array nums and an integer k, return the k most frequent elements. length+1. Next, we sort the buckets by frequency, and the top k k buckets are the top k k most frequent elements. After that, we would select the top k frequent elements. Input: nums = [1,1,1,2,2,3], k = 2 Output: [1,2] Here is my code: Bu videoda biz LeetCode 347 — Top K Frequent Elements masalasini Bucket Sort yondashuvi bilan yechamiz. 🎥 In this comprehensive video lecture on solving LeetCode Problem 347, we delve into various strategies for efficiently finding the top k frequent elements in a given array. Bucket Sort is optimal (O (n)), especially when working with frequency-based problems. Better than official and forum solutions. Traverse the frequency buckets from highest to lowest to collect the k most frequent elements. Jan 5, 2025 · Efficiently Solving Top K Frequent Elements Using Bucket Sort in Java In the world of coding challenges and algorithm design, the problem of finding the top k frequent elements in an array often May 14, 2021 · Top K Frequent Elements - Bucket Sort - Leetcode 347 - Python NeetCode 1M subscribers Subscribe =======2 APPROACHES + FROM INTUITION BUILDING TO COMPLETE SOLUTION=======Hi everyone, this is the 6th video of our Heap Playlist. Feb 20, 2024 · A detailed dry run of the implementation showcases the efficiency of the bucket sort algorithm in identifying the top K frequent elements. io/ - A better way to prepare for Coding Interviews🐦 Twitter: https://twitter. Campus bikes 280. I sorted the frequencies. Top K Frequent Elements in Python, Java, C++ and more. At every position (Position → Frequency), there will be a bucket (list) that contains all elements having the same frequency. And return the top k elements. In this video we will try to Can you solve this real interview question? Top K Frequent Elements - Given an integer array nums and an integer k, return the k most frequent elements. . This is a common problem in interviews because it tests knowledge of arrays, hash maps, heaps, and sorting. Oct 9, 2008 · Your solution (1) is an O (n) bucket sort replacing a standard O (n lg n) comparison sort. Top K Frequent Elements 347. Tags: array, hash-table, heap, bucket-sort, quickselect. This is a common interview problem that can be solved efficiently using three distinct approaches: Sorting, Heap, and Bucket Sort. Recommended Time & Space Complexity Hint 1 A naive solution would be to count the frequency of each number and then sort the array based on each element’s frequency. For example, a min-heap of size k can store the top k frequencies seen so far. It would also seem that with the Bucket Sort that creating the full list of num elements to take the first k elements does not cause too much of a penalty. Approach 1: Using min heap Instead of sorting the list as explained before Excited to share my new Medium article on solving LeetCode 347: Top K Frequent Elements 🎯 In this write-up, I break down two popular approaches — Heap (O (n log k)) and Bucket Sort (O (n Mar 19, 2024 · 今天的題目是：Top K Frequent Elements。 題目的描述很簡短，如下： 給予一個整數陣列 nums 跟一個整數 k，要回答的是在這個整數陣列中，最頻繁出現的 Super Repository for Coding Interview Preperation. The maximum frequency cannot exceed the size of the array n. Consideration A potential complication arises in situations of frequency ties. But Im struggling to pull these items out. length <= 10^4. Top K Frequent Elements - Bucket Sort - Leetcode 347 - Rust | 0ms Solution 🔥 Lagrange theorem in group theory Important Questions VBSPU Math Bsc 3rd semester math Today, we're taking a look at top k frequent elements and how to solve it using bucket sort. This problem is based on hea Can you solve this real interview question? Top K Frequent Elements - Given an integer array nums and an integer k, return the k most frequent elements. highest frequency) and collect the top k most frequent elements into a return View edward930908's solution of Top K Frequent Elements on LeetCode, the world's largest programming community. LeetCode solutions in any programming language347. Search in Rotated Sorted Array II 153. Sorting the entire list based on frequency takes O(n log n) time, where n is the number of unique elements. For example, Input: nums = [2,2,3,1,1,1], k = 2 Output: [1,2] Explanation: The 2 most frequent 347. Your solution (2) runs in time O (n lg k) -- that is, O (n) to iterate over all words and O (lg k) to add each one into the heap. In this video, we solve LeetCode Problem 347 — Top K Frequent Elements using Rust 🦀. Feb 23, 2024 · Bucket sort Another neat trick I learned from this leetcode problem was to use bucket sort to complete the task. That's O(n log k) time compl Arrays - Top K Frequent ElementsContents Solution 1 - using sorting, find number of times each element appeared and then sort them by that count Solution 2 - using Min Heap, find number of times each element appeared and then add to min heap with at most 'k' elements Solution 3 - using QuickSelect algorithm Solution 4 - using a technique used in BucketSort (easy and most efficient solution) solutions to LeetCode problems, along with explanations - IMperiumX/leetcode-solutions Mar 18, 2017 · Now, since, we cannot use regular sorting approach, another thing that comes to mind is, bucket sort. This brute force method is simple but inefficient for large lists. 0:00 Read the Problem0:43 Unoptimized Hashmap Solution 2:03 Bucke Today I solved Top K Frequent Elements from NeetCode150 using Bucket Sort (O(n)). Practice Top K Frequent Elements, a Medium level DSA problem. The Top K Frequent Elements problem on LeetCode is a classic problem that asks you to return the k most frequent elements in a given array of integers. Jul 23, 2025 · Bucket sort is a sorting technique that involves dividing elements into various groups, or buckets. Masalada eng ko‘p uchraydigan k ta elementni topish kerak bo‘ladi. So, if the input array is {1 You should definitely expect follow up questions to describe what data structures/algorithms you would use if you had to implement it without helper functions (heaps, bucket sort, etc) as well as the run time LeetCode 347 - Top K Frequent Elements - Bucket Sort - Hash Map - Python Solution satya the dev 29 subscribers Subscribe Constraints: 1 <= nums. Always check if Solve LeetCode 347: Top K Frequent Elements in under 30 seconds! 🚀 This medium-level problem teaches you how to use Hash Tables, Heaps (Priority Queue), and Bucket Sort to quickly find the most Approaches 1. Learn how to leverage min-heaps, bucket sort, and traditional sorting methods, with detailed complexity analysis and Python implementations for optimal performance. May 21, 2025 · LeetCode Medium #347 | Top K Frequent elements | BucketSort - The Easy and Efficient O (n) way Z2C 4 subscribers Subscribed Dec 2, 2024 · Method 3 - Bucket Sort 🏆 We can use array of linked list, where we can bucketize the numbers based on there frequency. Top K Frequent Elements - Bucket Sorting, Programmer Sought, the best programmer technical posts sharing site. We can improvise on this. Dec 20, 2023 · Master Data Structures & Algorithms for FREE at https://AlgoMap. Steps: Create a hashmap to count the frequency of each element. Note: You may assume k is always valid, 1 ≤ k ≤ number of unique elements. This guide will walk you through three effective methods to solve this problem: using a HashMap with sorting, Min-Heap, and Bucket Sort. The solution must account for how to prioritize numbers when multiple values share the same count. Top K Frequent Elements - Leetcode 347 | 4 Approaches including Min Heap and Bucket Sort Mar 26, 2024 · Every iteration of the inner loop will append one element to most_frequent. google. Includes time and space complexity analysis. Learn how to efficiently count element frequency, use a HashMap, and apply bucket sort to find the most Jul 12, 2025 · 🚀 Approach: Bucket Sort (Linear Time) Instead of sorting elements by frequency (which takes O(n log n)), we use a bucket sort trick to solve it in O(n). The bucket index will be frequency, values will be number added to that bucket. -1000 <= nums[i] <= 1000 1 <= k <= number of distinct elements in nums. io/Code solutions in Python, Java, C++ and JS for this can be found at my GitHub repo here: h Solution: Using priority Queue This problem is quite similar to top frequent words, except that it doesn't require the order of it's elements. Why n + 1? Apr 13, 2021 · But the Bucket Sort, at least for this input, definitely is more performant. Then, these smaller arrays can be sorted, like Bucket Sort 791. After building the frequency map, sort the elements in decreasing order of their frequency. Most people sort the numbers. Number of buckets will be = nums. Find Minimum in Rotated Sorted Array 154. This helps in avoiding edge cases, where we need Nov 3, 2018 · I am working on an interview question where I need to return the k most frequent elements given a non-empty array of integers. For example, the string "implementation" can be abbreviated in several ways, such as: "i12n" -> ("i mplementatio n") "imp4n5n" -> ("imp leme n tatio n") "14" -> (" implementation ") "implemetation In-depth solution and explanation for LeetCode 347. Top K Frequent Elements 1057. , all elements appearing 3 times go into bucket 3). Dec 29, 2023 · Top K Frequent Elements - LeetCode 347 - Heap - Bucket Sort? - Python - Malayalam | Google Interview WeCode Malayalam 9. Key Insights Count the frequency of each element using a hash table. Once the list most_frequent reaches size k, the function will terminate. #leetcode #coding #programming #datastructure #cpp Leetcode 347. Oct 2, 2025 · 🚀 Takeaways Heap-based approach is intuitive and works well when k is small compared to n. Your approach requires additional space for the bucket structure, but comparison sorts can be done in place. g. May 30, 2022 · Top K Frequent Elements - Bucket Sort - Leetcode 347 - JavaScript coderfact 1. Apr 15, 2022 · Find Top K Frequent Elements – Java Code In this example, Let’s discuss how we can solve this problem using bucket sort, and then we will write its java code. Questions in English: https://docs. Let’s go through solutions from brute force to optimal, focusing on different approaches with increasing efficiency. Traverse the bucket in reverse order (high frequency to low) and collect top k elements. You may return the answer in any order. Let’s look at 3 different approaches which have better time complexity. First Bad Version 162. Why? Because what if all the element occur once, then it is nums. 37K subscribers Subscribe Oct 29, 2025 · [Naive Approach] Using Hash map and Sorting The idea is to use a hashmap to store each element along with its frequency, allowing insertion and updates in constant time. Once I did that, I have an array ordered_arr which follows this exact design. Sorting Intuition: The most straightforward way to find the top k frequent elements is to count the frequency of each element using a hashmap, then sort the elements based on their frequency in descending order, and finally pick the first k elements from this sorted list. Find Peak Element in O (logn) LintCode 183. In this video we look at example test cases on how to determine the top k frequent elements efficiently using the bucket sort algorithm. Funny thing is that my initial method of solving the problem involved using the same amount of space and more time than the solution I learned from neetcode Decoding the 'Top K Frequent Elements' Problem with Bucket Sort! 🔍 #Day17 of #100DaysOfCode Hello LinkedIn Community! 🚀 Today, I took on the 'Top K Frequent Elements' problem on LeetCode About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket © 2024 Google LLC. (Here, “bucket” means an array of lists of size n + 1). Bucket Sort Algorithm Create an array of empty buckets Feb 23, 2024 · Solving the LeetCode Top K Frequent Elements problem. We can use a priority queue to keep track of the most frequent element. Alternative approaches include using heaps or Quickselect, but bucket sort meets the follow-up requirement of better than O (n log n) time I created a bucket sort but the array ended looking like this 3 2 1 0 0 0 which is how he described it in his video. The time complexity of the solution is O (n), as it involves iterating through the array only once. Hello, everyone! I appreciate all of you joining me whenever I have the chance to share some insights and solutions – it's great to be able to add fresh cont Find the k most frequent elements in an integer array. Heaps are excellent for maintaining top elements in streaming or selection problems. Another insight: since frequencies range from 1 up to n, you can use a bucket sort style approach. All of this along with a dry-run of code in JAVA. auqmac tzpgt uiyhngq hteivjj icfimkf slyw fecl lxeuw tjtic xptiqp nrgs pnzl mvi yejmk wfurg