#leetcode articles

Stop Solving Array Problems Randomly: 5 Patterns Every Developer Should Know

A practical guide to Two Pointers, Sliding Window, Prefix Sum, Kadane's Algorithm, and how to recognize the right pattern before writing code

12 min readmayankdev.hashnode.dev

Linkjob AINov 4

Matrix Diagonal Sum (LeetCode 1572): One Loop, One Center Check

Problem. Given a square matrix mat, return the sum of its primary diagonal and its secondary diagonal. If the size is odd, the center cell sits on both diagonals, so count it only once. The idea For r

2 min readlinkjob-ai.hashnode.dev

Linkjob AINov 3

Longest Harmonious Subsequence (LeetCode 594): Count Once, Check Neighbours

A harmonious array is one where the maximum and minimum differ by exactly 1. Given an array, return the length of its longest harmonious subsequence. The word "subsequence" is the whole trick: order d

2 min readlinkjob-ai.hashnode.dev

Linkjob AINov 3

Palindrome Linked List (LeetCode 234): O(1) Space Without Losing the List

Given the head of a singly linked list, return true if it reads the same forward and backward. Easy version: copy to an array Push every value into a list and compare it with its reverse. That's O(n)

2 min readlinkjob-ai.hashnode.dev