The Insert Interval problem involves inserting a new interval into a sorted list of non-overlapping intervals and merging any overlapping intervals. Think of it like scheduling a new meeting in a calendar: you add the meeting and merge it with existing ones if they overlap, ensuring the schedule remains clean…
N-Queens – 51. LeetCode
The N-Queens problems asks us to place N queens on an N * N chessboard such that no two queens threaten each other. The means no two queens can bin the the same row, column, or diagonal. The challenge is to find all possible configurations of the board that satisfy…
Longest Repeating Character Replacement – 424. LeetCode
The Longest Repeating Character Replacement problem asks us to find the length of the longest substring in a string s that can be transformed into a substring with all identical characters by replacing at most k characters. For example, in the string “AABABBA” with k = 1, the longest substring…
Valid Anagram – 242. Leetcode
An anagram is a word or phrase formed by rearranging the letters of another word or phrase. For example, “listen” and “silent” are anagrams. This problem asks you to determine if two given strings are anagrams of each other, but it should also work with Unicode characters like emojis or…
First Unique Character In A String – 387. LeetCode
The “First Unique Character in a String” problem asks you to find the index of the first character in a string that appears only one. If no such character exists, return -1. This problem is about efficiently identifying a character that is unique while processing all the characters in the…
Search In Rotated Sorted Array – 33. LeetCode
The “Search in Rotated Sorted Array” problem involves finding a target value in a sorted array that’s been rotated at some unknown pivot. For instance, an array like [4,5,6,7,0,1,2] is a rotation of [0,1,2,4,5,6,7]. You’re given this rotated array and a target value; your goal is to determine the target’s…
Maximum Product Subarray – 152. LeetCode
The Maximum Product Subarray problem asks you to find the highest possible product from any sequence of consecutive numbers (or “subarray”) within a given list of integers. You’re not just looking for the largest single number, but rather the maximum product you can achieve by multiplying a series of numbers…
3Sum – 15. LeetCode
The threeSum problem is a classic question that aims to find all unique triplets in an array that add up to zero. Given an integer array nums, the goal is to return a list of lists where each list represents a unique triplet that satisfies this condition. Solving this problem…
Rotate Array – 189. LeetCode
The “Rotate Array” problem on LeetCode asks us to rotate an array of integers to the right by a given number of steps k . This means each element in the array moves k positions to the right, with elements at the end wrapping around to the beginning. The challenge…
Find Customer Referee – 548. LeetCode
The LeetCode problem “Find Customer Referee” requires us to retrieve the names of customers who either have no referee or whose referee is not customer ID 2. High-Level Strategy To solve this problem: 1. Filter by Conditions: Use SQL’s WHERE clause to apply conditions that exclude customers with referee_id =…
