Two Pointers

Three animated two-pointer techniques to solve Three different problems. — As a self-taught developer (no theoretical CS background), learning data structures and algorithms later in your career is crucial. One of the algorithms or techniques widely used for both array and linked list problems is the “two-pointer technique”. …

3Sum - LeetCode Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared…leetcode.com Given an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that i != j, i != k, and j != k, and nums[i] + nums[j] + nums[k] == 0. Notice that the solution set must not contain duplicate triplets. Solution: Approach 1: Bruteforce

Problem Given two strings s and t, return true if s is a subsequence of t, or false otherwise. A subsequence of a string is a new string that is formed from the original string by deleting some (can be none) of the characters without disturbing the relative positions of the…

Runtime: 205 ms, faster than 45.45% of Python3 online submissions for Two Sum II — Input Array Is Sorted. Memory Usage: 14.8 MB, less than 88.44% of Python3 online submissions for Two Sum II — Input Array Is Sorted. Problem Description Given a 1-indexed array of integers numbers that is…

While the concept is two pointers converging from opposite sides, the implementation is more in a dp form. Description Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining. Examples Example 1: Input: height =…

A phrase is a palindrome if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forward and backward. Alphanumeric characters include letters and numbers. Given a string s, return true if it is a palindrome, or false otherwise. Example 1: Input: s…

[Leetcode practice] — 31. Next Permutation Question A permutation of an array of integers is an arrangement of its members into a sequence or linear order. For example, for arr = [ …

· Important points · Types of Two Pointers · Sample Problem · Problems · 3.1 Collision · 3.2 Forward · 3.3 Parallel · References Important points Physical significance of the pointer → range → pair (i, j) How to initialize the pointer How to change the pointer / move the pointer When…

The Two Pointers Technique is a technique that allows you to optimize your runtime (time complexity and often space complexity) By utilizing some ordering data. It’s generally applied on arrays and linked lists. The approach has 3 steps: Initialization: Starting points. …