Leetcode 448. Find All Numbers Disappeared in an Array
Problem statement You are given an array nums of n integers, where each integer nums[i] falls within the range [1, n]. Your task is to find and return an...
Leetcode 59. How To Go Around A Square Matrix In Spiral Order
Problem statement Given a positive integer n, generate an n x n matrix filled with elements from 1 to n^2 in spiral order. Example 1 Input: n = 3 Output:...
Leetcode 120. How To Find The Minimum Path From Top To Bottom Of A Triangle
Problem statement You're provided with a triangle array. Your goal is to find the smallest possible sum of a path from the top of the triangle to the bottom....
Leetcode 3. How To Find The Longest Substring Without Repeating Characters
Problem statement Given a string s, your task is to determine the length of the longest substring within s that does not contain any repeating characters....
Leetcode 342. How to Check If a Number is a Power of Four
The math and the bit behind a power of four.
Leetcode 1695. How To Find The Maximal Subarray Having Distinct Elements
Problem statement You have an array of positive integers called nums, and you wish to remove a subarray from it that consists of distinct elements. The score...
Leetcode 63. How To Count Unique Paths In A Grid With Obstacles
Problem statement You're given an m x n grid represented as an integer array called grid. In this grid, there is a robot initially located at the top-left...
Leetcode 2. How To Add Two Numbers Represented As Linked Lists
Problem statement You have two linked lists that represent non-negative integers. The digits of these numbers are stored in reverse order, with each node...
Leetcode 804. How to Encode Morse Code
Problem statement The problem involves the International Morse Code, which defines a standard way to encode letters with dots and dashes. Each English letter...
Leetcode 387. How to Perform a Counting Using Array and Hash Table
Problem statement You have a string called s. Your objective is to locate the index of the first character in the string that does not repeat anywhere else...
Leetcode 13. How to Convert a Given Roman Numeral to its Equivalent Integer Value
Problem statement Roman numerals utilize seven symbols: I, V, X, L, C, D, and M to represent numbers. Symbol Value I 1 V 5 X 10 L 50 C 100 D 500 M 1000 For...
Leetcode 235. How To Find a Nearest Common Ancestor In a Binary Search Tree
Problem statement Given a binary search tree (BST), find the lowest common ancestor (LCA) node of two given nodes in the BST. According to the definition of...
Leetcode 729. How to Define a Custom Comparison For a std::set
Problem statement You're creating a program to use as your calendar. You can add new events to the calendar, but only if adding the event will not lead to a...
Leetcode 378. How To Find The Kth Smallest Element in a Sorted Matrix
Problem statement You are given an n x n matrix where each row and column is sorted in ascending order. Your task is to find the k-th smallest element in...
Leetcode 890. How To Find The Strings of a Given Pattern
Problem statement You are provided with a list of strings named words and a string named pattern. Your task is to find the strings from words that match the...
Leetcode 242. How To Check If a String Is a Valid Anagram
Problem statement You are given two strings, s and t. Your task is to determine whether t is an anagram of s. If t is an anagram of s, return true;...
Leetcode 797. How to Find All Paths From a Source to a Target in a Graph
Find all paths from the source to the target in a directed acyclic graph using Depth-First Search.
Leetcode 739. How Long To Reach A Warmer Day
Problem statement You are given an array of integers temperatures, which represents the daily temperatures. Your task is to create an array answer such that...
Leetcode 876. How To Find The Middle Node of a Linked List
Problem statement Given the head of a singly linked list, return the middle node of the linked list. If there are two middle nodes, return the second middle...
Leetcode 368. How To Find The Largest Divisible Subset of a Given Integer Set
Find the largest subset of distinct positive integers where each element is a multiple of another, represented using index mapping for optimal performance.
Leetcode 509. How To Compute Fibonacci Number F(n)
Problem statement The Fibonacci numbers make up a sequence denoted as F(n), known as the Fibonacci sequence. Each number in this sequence is the sum of the...
Leetcode 922. How To Arrange An Array In Parity
Sort given array by parity with different solutions: Bubble Sort and Two Pointer approach.
Leetcode 929. How To Uniquify Email Addresses
Problem statement Each valid email address is composed of a local name and a domain name, separated by the '@' sign. The local name may contain lowercase...
Leetcode 78. How To Generate All Possible Subsets of a Given Integer Set
Problem Statement Given an integer array nums of unique elements, return all possible subsets (the power set). The solution set must not contain duplicate...
Leetcode 1710. How To Put As Many Things As You Can On a Truck
Maximize units loaded onto the truck by prioritizing boxes with more units.
Leetcode 80. How To Remove Duplicates From a Sorted Array
Removing duplicates from a sorted array in-place, keeping each unique element at most twice.
Leetcode 21. How To Merge Two Sorted Linked Lists
Merge two sorted linked lists into a single sorted linked list efficiently using C++.
Leetcode 1260. How To Shift Elements of a Matrix
Perform k shift operations on a 2D grid to return the updated grid.
Leetcode 48. How to Rotate a Square Matrix
Rotate a square matrix 90 degrees clockwise in two steps: transpose and mirror vertically in place.