JZLeetCode

High quality leet code solutions in Java, Python, C++, and Rust.

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Featured

• LeetCode 658 LintCode 460 Find K Closest Elements

  Published:Mar 24, 2025 |  at 06:23 AM

  Solutions for LeetCode 658 LintCode 460, medium, tags: array, binary-search, sliding-window, sorting, heap; companies: google.

• LeetCode 2539 LintCode 3855 Count the Number of Good Subsequences

  Published:Mar 21, 2025 |  at 06:23 AM

  Solutions for LeetCode 2539 LintCode 3855, hard, tags: enumerate, string, hash table, math, combinatorics, counting.

• System Design - How do Websockets Work

  Published:Mar 15, 2025 |  at 06:23 AM

  How do websockets work comparing to http?

• LeetCode 2450 LintCode 3841 Number of Distinct Binary Strings After Applying Operations

  Updated:Feb 22, 2025 |  at 06:23 AM

  Solutions for LeetCode 2450 LintCode 3841, medium, tags: math, string.

• LeetCode 206 LintCode 35 Reverse Linked List

  Published:Jan 30, 2025 |  at 06:23 AM

  Solutions for LeetCode 206 LintCode 35, easy, tags: linked list, recursion; companies: bytedance.

• LeetCode 1166 LintCode 3677 Design File System

  Published:Jan 28, 2025 |  at 06:23 AM

  Solutions for LeetCode 1166 LintCode 3677, medium, tags: hash table, trie, string, design.

• How could we interview job candidates to find the right teammates? Why should we care?

  Updated:Jan 23, 2025 |  at 10:12 AM

  how should we interview other job candidates to find the teammates we like? tips and suggestions on how to interview teammate or junior engineers.

• LeetCode 2017 Grid Game

  Published:Jan 20, 2025 |  at 06:23 AM

  Solutions for LeetCode 2017, medium, tags: array, prefix sum, dynamic programming, matrix.

• LeetCode 542 LintCode 974 01 Matrix and LeetCode 1765 Map of Highest Peak

  Published:Jan 19, 2025 |  at 06:23 AM

  Solutions for LeetCode 542, LeetCode 1765, and LintCode 974, hard, tags: array, queue, sliding window, heap, monotonic queue.

• LeetCode 532 LintCode 1187 K-diff Pairs in An Array

  Published:Jan 17, 2025 |  at 06:23 AM

  Solutions for LeetCode 532 LintCode 1187, medium, tags: array, hash table, counting, two-pointers, binary-search; companies: nvidia, amazon.

• LeetCode Meeting Rooms Derivative Question

  Published:Jan 10, 2025 |  at 06:23 AM

  Solutions for meeting rooms derivative question, hard, tags: heap, line sweep, ordered map; companies: salesforce.

• LeetCode 1400 Construct K Palindrome Strings

  Published:Jan 9, 2025 |  at 06:23 AM

  Solutions for LeetCode 1400, medium, tags: hash table, string, greedy, counting.

• LeetCode 916 LintCode 1726 Word Subsets

  Published:Jan 8, 2025 |  at 06:23 AM

  Solutions for LeetCode 916 LintCode 1726, medium, tags: array, hash table, string.

• System Design - Event Loop for Concurrent Applications

  Published:Jan 6, 2025 |  at 06:23 AM

  event loop system design pattern/construct event loop (message dispatcher), reactor/actor pattern, non-blocking mechanism for concurrent applications

• LeetCode 1930 Unique Length-3 Palindromic Subsequences

  Published:Jan 5, 2025 |  at 06:23 AM

  Solutions for LeetCode 1930, medium, tags: hash table, string, bit manipulation, prefix sum.

• HackerRank and GeeksForGeeks Minimum Replacements/Substitutions to Make Adjacent Characters Unequal

  Published:Jan 2, 2025 |  at 06:23 AM

  Solutions for , easy, tags: array, sliding window; companies: salesforce.

• LeetCode 2559 Count Vowel Strings in Ranges

  Published:Dec 31, 2024 |  at 06:23 AM

  Solutions for LeetCode 2559, medium, tags: array, string, prefix-sum.

• LeetCode 1422 Maximum Score After Splitting a String

  Published:Dec 30, 2024 |  at 06:23 AM

  Solutions for LeetCode 1422, easy, tags: string, prefix sum.

• HackerRank Programmer Strings

  Published:Dec 29, 2024 |  at 06:23 AM

  Solutions for HackerRank Programmer Strings, hard, tags: string, hash table.

• LeetCode 2466 LintCode 3854 Count Ways to Build Good Strings (Number of Good Binary Strings)

  Published:Dec 28, 2024 |  at 06:23 AM

  Solutions for LeetCode 2466 LintCode 3854, medium, tags: array, dynamic programming.

• Java CheatSheet

  Updated:Dec 26, 2024 |  at 10:12 AM

  tips for using java

• LeetCode 875 LintCode 1492 Koko Eating Bananas

  Published:Dec 24, 2024 |  at 06:23 AM

  Solutions for LeetCode 875 LintCode 1492, medium, tags: array, binary search; companies: facebook, salesforce.

• LeetCode 423 LintCode 1247 Reconstruct Original Digits from English

  Published:Dec 19, 2024 |  at 06:23 AM

  Solutions for LeetCode 423 LintCode 1247, medium, tags: hash table, simulation, math, string.

• LeetCode 2415 Reverse Odd Levels of Binary Tree

  Published:Dec 18, 2024 |  at 06:23 AM

  Solutions for LeetCode 239, hard, tags: array, queue, sliding window, heap, monotonic queue.

• LintCode 2503 Thread Safe Counter (Concurrency)

  Published:Dec 18, 2024 |  at 06:23 AM

  Solutions for LintCode 2503, tags: lock, re-entrant lock.

• LeetCode 691 LintCode 1081 Stickers to Spell Word

  Published:Dec 17, 2024 |  at 06:23 AM

  Solutions for LeetCode 239, hard, tags: array, queue, sliding window, heap, monotonic queue.

• LeetCode 339 LintCode 551 Nested List Weight Sum

  Published:Dec 15, 2024 |  at 07:23 AM

  Solutions for LeetCode 339 LintCode 551, medium, tags: dfs, bfs; companies: salesforce.

• Analyze Recursive Algorithm Time Complexity for LeetCode Questions with Substitution, Recursion Tree and Master Theorem

  Published:Dec 15, 2024 |  at 06:23 AM

  Analyze Recursive Algorithm Time Complexity for LeetCode Questions with Substitution, Recursion Tree and Master Theorem

• Generative AI (Artificial Intelligence) with Large Language Models (LLM) - Part 1

  Updated:Dec 14, 2024 |  at 10:12 AM

  generative AI (artificial intelligence) machine learning with large language models

• LeetCode 994 LintCode 3726 Rotting Oranges

  Published:Dec 13, 2024 |  at 06:23 AM

  Solutions for LeetCode 994 LintCode 3726, medium, tags: graph, bfs, array; companies: tiktok.

• LeetCode 520 LintCode 1202 IPO

  Published:Dec 12, 2024 |  at 06:23 AM

  Solutions for LeetCode 520 LintCode 1202, hard, tags: array, heap, greedy, sorting, binary search, dynamic programming, quick select.

• Rust Option, Rc, and RefCell Explained - LeetCode Tree Node and LinkedList Node

  Published:Dec 11, 2024 |  at 07:23 AM

  Explanation for rust data structure for tree node and linked list node. What is Rc and RefCell? Why Option<Rc<RefCell>>> three wrappers? How to avoid circular reference?

• LeetCode 2558 Take Gifts From the Richest Pile

  Published:Dec 11, 2024 |  at 06:23 AM

  Solutions for LeetCode 2558, easy, tags: array, heap, simulation.

• LeetCode 713 LintCode 1075 Subarray Product Less Than K

  Published:Dec 10, 2024 |  at 06:23 AM

  Solutions for LeetCode 713 and LintCode 1075, medium, tags: sliding window, two pointers, prefix sum; companies: salesforce, yatra.

• LeetCode 1650 LintCode 474 Lowest Common Ancestor of a Binary Tree III

  Published:Dec 9, 2024 |  at 07:23 AM

  Solutions for LeetCode 1650 LintCode 474, medium, tags: binary tree, hash table, two pointers; companies: microsoft.

• LeetCode 408 LintCode 637 Valid Word Abbreviation

  Published:Dec 9, 2024 |  at 06:23 AM

  Solutions for LeetCode 408 LintCode 637, easy, tags: two pointers, string, companies: facebook, google.

• HackerRank GET Requests for GIF Images

  Published:Dec 8, 2024 |  at 06:23 AM

  Solutions for hacker rank get requests for gif images, medium, tags: file, hash set.

• LintCode 26 Inner Product

  Published:Dec 6, 2024 |  at 06:23 AM

  Solutions for LintCode 26, hard, tags: dynamic programming.

• How to Draw Circles and Arcs with Python Library Matplotlib

  Updated:Dec 5, 2024 |  at 10:12 AM

  tips for matplotlib python draw arcs, robot walks, project euler 208

• LeetCode 540 LintCode 1183 Single Element in a Sorted Array

  Published:Dec 5, 2024 |  at 06:23 AM

  Solutions for LeetCode 540 LintCode 1183, medium, tags: array, binary search.

• Linux Cheatsheet, tips and Commands

  Updated:Dec 4, 2024 |  at 10:12 AM

  tips for linux commands and tips

• LeetCode 1 LintCode 56 Two Sum

  Published:Dec 4, 2024 |  at 06:23 AM

  Solutions for LeetCode 1 LintCode 56, easy, tags: array, hash table.

• HackerRank Robot Walks and Project Euler 208 Solutions

  Published:Dec 3, 2024 |  at 06:23 AM

  Solutions for project euler 208 and hackerrank question robot walks, hard, tags: math, simulation.

• How to Install SortedContainers in the Python Shell or With a Python Script

  Updated:Dec 1, 2024 |  at 10:12 AM

  tips for installing sortedcontainers in a python shell

• LeetCode 53 LintCode 41 Maximum Subarray

  Published:Dec 1, 2024 |  at 08:23 AM

  Solutions for LeetCode 53 and LintCode 41, medium, tags: array, divide and conquer, dynamic programming, prefix sum, companies: ltk.

• LeetCode 1041 LintCode 1345 Robot Bounded in Circle (GeeksForGeeks, HackerRank EnCircular)

  Published:Nov 30, 2024 |  at 07:23 AM

  Solutions for LeetCode 1041 LintCode 1345 GFG HackerRank, medium, tags: math, string, simulation, companies: linkedin, salesforce.

• LintCode 3127 How Many Times is Two Squared?

  Published:Nov 30, 2024 |  at 06:23 AM

  Solutions for LintCode 3127, easy, tags: math, bit.

• LeetCode 1346 Check If N and Its Double Exist

  Published:Nov 29, 2024 |  at 06:23 AM

  Solutions for LeetCode 1346, easy, tags: array, hash table, two pointers, binary search, sorting.

• LeetCode 91 Decode Ways and Hacker Rank ASCII Encoded Strings (VMWare, Goldman Sachs, and Salesforce Interview Questions)

  Published:Nov 28, 2024 |  at 07:23 AM

  Solutions for LeetCode 91, medium, tags: string, dynamic programming, companies: goldman sachs, vmware, salesforce.

• Cheatsheet for Math Knowledge Needed for LeetCode Algorithm Questions (Geometric Series and Arithmetic Progression Sum)

  Published:Nov 28, 2024 |  at 06:23 AM

  cheatsheet for math knowledge needed for leetcode algorithm questions, geometric series sum

• HackerRank Bitwise Xor Operations

  Published:Nov 27, 2024 |  at 08:23 AM

  Solutions for hackerrank bitwise xor operations, medium, tags: bit, companies: salesforce.

• Fun Bit Tricks (Manipulations)

  Published:Nov 26, 2024 |  at 10:23 AM

  Fun bitwise tricks such as count set bits, negate, ilog2, xor swap, .etc.

• LeetCode 3167 HackerRank Better Compression

  Published:Nov 26, 2024 |  at 07:23 AM

  Solutions for LeetCode 3167 HackerRank Better Compression, tags: string, hash table, companies: salesforce.

• LeetCode 214 LintCode 678 Shortest Palindrome (GeeksForGeeks Minimum Insertion to Form Shortest Palindrome)

  Published:Nov 26, 2024 |  at 06:23 AM

  Solutions for LeetCode 239, LintCode 678, medium, tags: two pointers, string, kmp, rabin-karp, rolling hash.

• LeetCode 146 LintCode 134 LRU Cache

  Published:Nov 24, 2024 |  at 09:23 AM

  Solutions for LeetCode 146 LintCode 134, medium, tags: hash, linked list, design, doubly linked list, companies: amazon, openai.

• LeetCode 487 LintCode 883 Max Consecutive Ones II

  Published:Nov 24, 2024 |  at 08:23 AM

  Solutions for LeetCode 487, LintCode 833, medium, tags: array, dynamic programming, sliding window, two pointers, companies: google.

• LeetCode 1 Similar Two Subtract Count

  Published:Nov 24, 2024 |  at 07:23 AM

  Solutions for LeetCode 1 similar, medium, tags: array, hash table, companies: salesforce.

• LeetCode 811 LintCode 1006 Subdomain Visit Count

  Published:Nov 24, 2024 |  at 06:23 AM

  Solutions for LeetCode 811 and LintCode 1006, medium, tags: array, hash, string, counting, companies: salesforce.

• LeetCode 1804 LintCode 3729 Implement Trie II

  Updated:Nov 23, 2024 |  at 09:23 AM

  Solutions for LeetCode 1804 LintCode 3729, medium, tags: design, trie, hash, string.

• Reverse of LeetCode 38 LintCode 420 Count and Say (Look and Say)

  Updated:Nov 23, 2024 |  at 08:23 AM

  Solutions for LeetCode 38, LintCode 420, medium, tags: math, string, simulation, companies: facebook, pinterest.

• LeetCode 38 LintCode 420 Count and Say (Look and Say)

  Updated:Nov 23, 2024 |  at 07:23 AM

  Solutions for LeetCode 38, LintCode 420, medium, tags: math, string, simulation, companies: facebook, pinterest.

• How to Embed an SVG Image/Picture with the Code or File on a Website

  Published:Nov 23, 2024 |  at 03:23 AM

  three main ways to embed an SVG image or picture as a file or using html code on a website

• Vim CheatSheet

  Updated:Nov 22, 2024 |  at 10:12 AM

  tips for using vim

• LeetCode 465 LintCode 707 Optimal Account Balancing

  Updated:Nov 22, 2024 |  at 07:24 AM

  Solutions for LeetCode 465 LintCode 707, hard, tags: bit, array, dynamic programming, backtracking, bitmask.

• Elevator Closest Floors (Shortest Path, Related to Shortest Seek Time First Disk Seek Algorithm)

  Updated:Nov 21, 2024 |  at 07:23 AM

  Solutions for Elevator Shortest Path, medium, tags: array, binary search.

• LeetCode 2461 Maximum Sum of Distinct Subarrays With Length K

  Published:Nov 17, 2024 |  at 07:23 AM

  Solutions for LeetCode 2461, medium, tags: array, sliding window, hash.

• LeetCode 1055 LintCode 3652 Shortest Way to Form String

  Published:Nov 17, 2024 |  at 05:23 AM

  Solutions for LeetCode 1055 LintCode 3652, hard, tags: greedy, two pointers, string.

• LintCode 2894 Order by frequency

  Updated:Nov 16, 2024 |  at 07:22 AM

  Solutions for LintCode 2894, medium, tags: map, sort. Related to LeetCode 884 and 451.

• LeetCode 125 LintCode 415 Valid Palindrome

  Updated:Nov 13, 2024 |  at 08:12 AM

  Solutions for LeetCode 125, LintCode 415, easy, tags: two pointers, string. Companies: LinkedIn, Facebook, Uber, Zenefits, Microsoft.

• LeetCode 314 LintCode 651 Binary Tree Vertical Order Traversal

  Updated:Nov 10, 2024 |  at 10:12 AM

  solutions for LeetCode 314 LintCode 651 Binary Tree Vertical Order Traversal, tags: hash, bfs, tree, companies: facebook google

• LeetCode 1192 LintCode 1271 Critical Connections in a Network

  Updated:Nov 10, 2024 |  at 10:12 AM

  solutions for LeetCode 1192, LintCode 1271, hard, tags: dfs, graph, bi-connected component. Companies: Amazon.

• LeetCode 239 LintCode 362 Sliding Window Maximum

  Updated:Nov 10, 2024 |  at 10:12 AM

  solutions for LeetCode 239, LintCode 362, hard, tags: array, queue, sliding window, heap, monotonic queue. Companies: Amazon, Zenefits, Microsoft, Google.

• LeetCode 20 LintCode 423 Valid Parentheses (stack)

  Updated:Nov 8, 2024 |  at 05:12 PM

  solution for LeetCode 20 LintCode 423 valid parentheses, tags: stack, string; companies: goldman sachs, twitter, airbnb, amazon, facebook, microsoft, bloomberg, uber, google.

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  Updated:Dec 7, 2024 |  at 10:12 AM

  tips for using AWS

• LeetCode 2257 Count Unguarded Cells in the Grid

  Updated:Nov 20, 2024 |  at 07:23 AM

  Solutions for LeetCode 2257, medium, tags: array, graph, simulation.

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• LeetCode 1652 Defuse the Bomb

  Updated:Nov 17, 2024 |  at 07:22 AM

  Solutions for LeetCode 1652, easy, tags: array, sliding window.