Two Pointer Template Leetcode. Apr 4, 2024 · The two-pointer technique is a widely used approac
Apr 4, 2024 · The two-pointer technique is a widely used approach to solving problems efficiently, particularly scenarios involving arrays or linked… The two-pointer approach uses two variables to trace over each element in a data structure. monster Valid Palindrome | LeetCode 125 | Two Pointer Solution Explained #coding #leetcode #programming 10 1 Share 2 days ago · Greedy strategy: Use two pointers (often start and end) and greedily move the pointer that improves the solution. The two-pointer technique I’m referring to here involves using two pointers that start at opposite ends of an array and gradually move towards each other before meeting in the middle. We mentioned two scenarios to use the two-pointer technique: Two pointers starts at different position: one starts at the beginning while another starts at the end; Two pointers are moved at different speed: one is faster while another one might be slower. include the first K elements of the data structure. Dec 9, 2025 · The ultimate comprehensive guide to two pointers. Level up your coding skills and quickly land a job. monster/ 👈 Best place to learn and practice coding interviewsAlmost all LeetCode problems can be solved with the same 8 patterns, and in this v Sep 24, 2024 · Two Pointers in 7 minutes | LeetCode Pattern AlgoMasterIO 196K views • 11 months ago 25:49 The only 14 patterns you'll ever need to master LeetCode Interviews! LeetCode was hard until I learned these patterns 14 patterns. So, I’m putting together this list of 20 questions that I believe are I've watched neetcodes solution and I'm still having a hard time understanding. There are around 140 problems today, but I only solved the public ones (117 problems). this is the key to understanding how sliding window works. Usually, the problems related to strings and arrays can be solved by brute force, which basically means your code searches all the possible solutions and returns the correct ones. By using two pointers instead of nested loops, we can often reduce the time complexity from O (n²) to O (n). 5 months, and wanted to share my findings/classifications here. Example 2: Input: s = "bbbbb" Output: 1 Explanation: The answer Jul 22, 2024 · The two-pointer technique uses two pointers (or indices) that traverse the data at the same time. io: https://neetcode. This guide builds your intuition with diagrams, examples, and a reusable decision process. Could someone please explain the two poitner solution to the container problem and also give me similar two pointer questions for practice? Thank you. Example 1: Input: s = "abcabcbb" Output: 3 Explanation: The answer is "abc", with the length of 3. I’ve been really obsessed with it. Jan 21, 2023 · One of these approaches goes by Two-Pointers and is the subject of this video. The only 14 patterns you'll ever need to master LeetCode Interviews! LeetCode was hard until I learned these patterns 14 patterns. ⭐️ Master the technical interview without endless grinding with AlgoMonster ⭐️ Apr 17, 2023 · Discover the nuances of using 'and' and 'or' conditions with the two pointers technique in LeetCode problems, demonstrated through merging two sorted lists. Compute the result for 1st window, i. Typically: @algo. FAANG Coding Interviews / Data Structures and Algorithms / Leetcode DSA Daily — Arrays | Two Pointers LeetCode 88: Merge Sorted Array Day 10 of staying consistent with problem solving 🧠 Problem in short We’re given two sorted arrays: nums1 (with extra space Feb 15, 2021 · Discussing Binary Search, and how to use its template code with Two Pointers to solve multiple interview questions in C#. May 24, 2019 · Two-pointer is a quite common method used to solve Leetcode problems related to strings, arrays and linked lists. io/practice If you found this helpful Author: @wkw, @ColeB2 | https://leetcode. Nov 28, 2025 · Two pointers show up everywhere on LeetCode, but many beginners memorize patterns without understanding why they work. Purpose and Overview The Two Pointers Technique is a fundamental algorithm pattern that uses two pointer variables to traverse a data structure (typically an array or linked list) simultaneously. I found some lists such as These Tips from Sean Prashad however I still find myself having to guess most of the time. In the first round, the slow pointer moves to two and the fast pointer moves to three. Google, Microsoft, Apple, Amazon এর interview তে এই problem টা বার বার আসে! 🔥 🚀 LeetCode 283 - Move Zeroes এর সবচেয়ে সহজ Two As the name suggests, the two-pointer approach can be used to help process two elements per loop, instead of just one. . fast/slow, front/back, etc. Valid Palindrome class Solution { public: bool isPalindrome (string s) { int left =0; int right = s. Note that "bca" and "cab" are also correct answers. The left_pointer should be pointing at the largest negative number (most negative), and the right_pointer should be pointing at the largest positive number. Feb 15, 2022 · Overview Sliding Window Technique is a popular method in algorithmic problems because of its high efficiency (mostly linear) It helps to avoid computing repetitive problems by computing only the new part that's introduced in the data set and discardi LeetCode Timer: Easily time your leetcode practise sessions with automatic time setting based on difficulty. At the start, both are at node one. 2 days ago · This is essentially how the Fast & Slow Pointers pattern works. The Two Pointers pattern is a technique that uses two pointers to iterate through a data structure (usually an array or linked list) in a single pass. Free NeetCode 150 67 / 150 completed Arrays & Hashing Two Pointers Sliding Window +14 more Help with Two Pointer techniques Hello, I have been working with the Two Pointer pattern for the past few days and am struggling with identifying when to use each type of two pointer (ie. com/problems/partition-labels/ 0838 - Push Dominoes (Medium) Let's briefly review this technique. What is the Two pointer method ? Sep 7, 2025 · Here’s a list of important Two Pointers problems on LeetCode, curated with their strategies and direct links. size () -1; // inside this only … Each time you increase the left pointer, you're knocking out all the substring/subarrays that are rooted at that left pointer (it's impossible to consider them again - and for good reason: the condition would not be satisfied by *any* subset rooted at that left pointer). The guide is organized into two main sections: first, how to recognize a two-pointers problem, and second, a ranked discussion of the techniques and approaches—from the most frequently used patterns to those that occur less often. Can you solve this real interview question? Minimum Size Subarray Sum - Given an array of positive integers nums and a positive integer target, return the minimal Level up your coding skills and quickly land a job. com/problems/permutation-in-string/ 0653 - Two Sum IV - Input is a BST (Easy) Author: @madhu915 | https://leetcode. I maintained a window with a running product of Jan 13, 2022 · Hello, I have been solving all two pointers tagged problems in last 3. Perfect for coding interview preparation. Acceptance Rate 66. Use this as a checklist or a guide to mastering this pattern. Get a $1,500 DISCOUNT on Tech Bootcamps!! RESUME Jun 14, 2024 · Two Pointers The Two Pointers technique is a fundamental and versatile approach used to Tagged with algorithms, datastructures, coding, interview. Depending on the difficulty, these pointers may go towards, away from, or in the same direction. Sep 2, 2025 · How to use Sliding Window Technique? There are basically two types of sliding window: 1. 5 % Topics Array Two Pointers Dynamic Programming Stack Monotonic Stack Companies Medium Medium Jul 26, 2025 · Two pointers is a pattern where you use two indices (or “pointers”) to traverse an array — either from both ends or from the same direction — to solve a problem more efficiently than brute force. For the purpose of this article, a pointer will simply be an integer that points to an index in an array or string object. The problem will ask us to return the maximum or minimum subrange Aug 15, 2023 · Today I solve and explain all 3 Blind75 Two Pointer Pattern problems live in one sitting. Mar 20, 2025 · Mastering the 2-Pointers Approach: A Comprehensive Guide Step-by-Step Solutions to Boost Your Problem-Solving Skills In this article, we’ll solve some leetcode questions for two pointers / … Dec 13, 2024 · Leetcode similar questions part 1 — problem solving patterns (two pointer) Keywords: leetcode, two sum, problems, competitive programming, software development, jobs This article presents one of … LeetCode Explore is the best place for everyone to start practicing and learning on LeetCode. NeetCode. So, we ought to use a two-pointer approach here. Two Sum - Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target. (Here, pointers are basically array indexes). Why it works: Moving the "less promising" pointer cannot miss a better solution. In this guide, we'll cover the basics so that you know when and Welcome to our ultimate guide on mastering the Two Pointers technique with the top 21 LeetCode problems! This session is perfect for anyone preparing for co Can you solve this real interview question? Minimum Size Subarray Sum - Given an array of positive integers nums and a positive integer target, return the minimal This document explains the Two Pointers Pattern, a fundamental algorithmic technique implemented across problems in the $1 directory. No matter if you are a beginner or a master, there are always new topics waiting for you to explore. good luck! Below is a detailed study guide that analyzes the Two Pointers problems from the collection. Sep 3, 2020 · Let's learn about the Two Pointers technique to algorithm templates and two main variations of this technique. This technique optimizes solutions from O (n²) to O (n) time complexity by eliminating the need for nested loops. If you are preparing for Jul 22, 2024 · The two-pointer technique uses two pointers (or indices) that traverse the data at the same time. Tech interviews. It involves using two pointers, one pointing to the beginning of the data set and the other pointing to the end, and moving them towards each other based on specific conditions. Two Pointers What is Two Pointers? Two Pointers is a technique used to iterate through a data structure, usually an array or linked list These pointers perform tasks such as searching, sorting or finding specific patterns within the data Related examples Read my solution to some LeetCode problems below Valid Palindrome Two Sum II - Input Array We can sequentially add the next biggest elements with the two pointer approach. There are two common scenarios in which the two-pointer approach is used. Fixed Size Sliding Window: The general steps to solve these questions by following below steps: Find the size of the window required, say K. If you are preparing for Level up your coding skills and quickly land a job. If you are preparing for technical interview, two pointers is one of the popular topics that you can't skip :). One, that would keep track of the current element in the original array and another one for just the unique elements. In one scenario, one pointer starts from the beginning and the other pointer starts from the end, moving toward one another until they Apr 3, 2025 · Leetcode 150- Act II: Two Pointers 125. Learn all variants, when to use each pattern, complete templates in multiple languages, and a systematic approach to solve any two pointers problem. Can you solve this real interview question? Longest Substring Without Repeating Characters - Given a string s, find the length of the longest substring without duplicate characters. Lately, I’ve been grinding on LeetCode, specifically on two-pointer questions 🚀. If you are preparing for We need to modify the array in-place and the size of the final array would potentially be smaller than the size of the input array. e. However, unlike the two-pass approach, the two-pointer technique provides us with a bit of flexibility to look-ahead, look-behind, and compare different windows of data. Master 41+ two pointers problems asked in technical interviews at Google, Amazon, Microsoft, Meta, Apple. 5 % Topics Array Two Pointers Dynamic Programming Stack Monotonic Stack Companies Medium Medium Dec 29, 2021 · I am trying to figure out what is the main difference between the Sliding Window and Two-pointer technique. LeetCode Problems solved in this video: Thanks for Watching! If you found this video helpful, check other Geekific Acceptance Rate 66. - ashishps1/awesome-leetcode-resources The two pointer technique is a near necessity in any software developer's toolkit, especially when it comes to technical interviews. Calculate trapped rain water using Two Pointer / Prefix Max approach 💧One of the most asked hard array problems 🚀#LeetCode #TwoPointer #DSA #Shorts Day 14 of Complete DSA Series in Java | Two Pointer Technique & In-Place Array Manipulation - Top FAANG QuestionsIn this lecture, I solve 3 essential array m Separate even and odd number Leetcode | DSA with Patterns | Two Pointers | Leetcode | Array DSA Journey – Day 13 🚀 LeetCode 713 – Subarray Product Less Than K Approach: Solved using the sliding window (two-pointer) technique. I maintained a window with a running product of 2 days ago · This is essentially how the Fast & Slow Pointers pattern works. Learn the two pointers pattern with step-by-step examples, code templates, and LeetCode practice problems. Oct 3, 2025 · Two Pointers Pattern in 10 Minutes ⏱ | LeetCode Patterns Series #01 for BeginnersTo get ahead with your Placement Prep, Fill this form now: https://docs. 06K subscribers Subscribed May 9, 2025 · Solve Leetcode — Two Pointer Pattern In this blog, let’s dive deep into two pointer method and understand how it works with simple examples. size () -1; // inside this only … Can you solve this real interview question? Longest Substring Without Repeating Characters - Given a string s, find the length of the longest substring without duplicate characters. Learn when to use opposite direction two pointers, common patterns, and how to avoid mistakes. Seem these topics are being asked in the interview very frequently so understanding them clearly is required. Practice 15 easy, 24 medium, and 2 hard two pointers coding challenges. Dec 9, 2025 · The ultimate comprehensive guide to two pointers. ). DSA. Jan 13, 2022 · Hello, I have been solving all two pointers tagged problems in last 3. In the second round, the slow pointer moves to three and the fast pointer moves to five. monster/ 👈 Best place to learn and practice coding interviewsAlmost all LeetCode problems can be solved with the same 8 patterns, and in this v Dec 9, 2025 · Master the converging pointers pattern with production-ready templates in Python, JavaScript, and Java. If you are preparing for The two pointers technique is a technique used to iterate through a data set, typically an array or a list, in a controlled way. The pattern uses two index variables that traverse an array or seq Level up your coding skills and quickly land a job. You may assume that each input would have exactly one solution, and you may not use the same element twice. More importantly, I am having a hard time generalizing the concept of two pointers to anything but summation questions. The slow pointer moves one step at a time and the fast pointer moves two steps at a time. Dec 29, 2021 · I am trying to figure out what is the main difference between the Sliding Window and Two-pointer technique. https://algo. com/problems/two-sum-iv-input-is-a-bst/ 0763 - Partition Labels (Medium) Author: @ColeB2 | https://leetcode. We first set a left_pointer at the left of the list and a right_pointer at the right of the list. Apr 3, 2025 · Leetcode 150- Act II: Two Pointers 125. Awesome LeetCode resources to learn Data Structures and Algorithms and prepare for Coding Interviews. Example 2: Input: s = "bbbbb" Output: 1 Explanation: The answer Oct 21, 2019 · In Coding Patterns series, we will try to recognize common patterns underlying behind each algorithm question, using real examples from Leetcode. Must-do List for Interview Prep Apr 1, 2022 · Two Pointers Career Concept Introduction Two pointer approach is an essential part of a programmer’s toolkit, especially in technical interviews. Nov 15, 2025 · Two Pointers is the most underrated pattern that appears in 100+ LeetCode problems, yet most people don't know when to use it. The name does justice in this case, it involves using two pointers to save time and space. Dec 21, 2019 · Sliding Window is an extension of the two pointer approach where we use two pointers (left and right) to create a “window”. For the purpose of this article, a pointer is an index of an array. Majority of them is in easy or medium so, if you understand the Dec 21, 2019 · An easy way to remember is a pointer points at another object. LeetCode Video Solutions: Watch free LeetCode video solutions on the problem page itself. After solving 500+ problems, I've broken down the Two Pointers Pattern into 5 categories that will make you spot these problems instantly in interviews. Jan 26, 2025 · Two Pointers in 7 minutes | LeetCode Pattern AlgoMasterIO 9. We need to modify the array in-place and the size of the final array would potentially be smaller than the size of the input array. It uses two pointers that traverse a sequence at different speeds. This is the best place to expand your knowledge and get prepared for your next interview. goog Nov 11, 2024 · In this video, we introduce the simple two-pointer intuitively to solve questions requiring two indices for an array at once.