Imagine you’re given a list of numbers and a target value. You need to figure out all the unique ways to combine these numbers so their total equals the target. You can use any number as many times as you want, but the order of numbers in the combination does…

Imagine you’re reading a sentence and trying to find the longest stretch of letters where no letter is repeated. The goal is to figure out the maximum length of such a stretch of unique characters without having to go through every possible combination. Brute Force Approach Optimal Approach Algorithm &…

Imagine you have two lists of numbers that are already sorted in order. You want to combine them and find the middle number (or the average of the two middle numbers if the total count is even). This middle value is called the “median”. The challenge is to do this…

Imagine you have two lists of numbers. For each number in the first list, you want to find the next larger number in the second list that comes after it. If no such number exists, you return -1. This problem is about efficiently finding these “next greater elements”. Brute Force…

In the Koko Eating Bananas problem, Koko the gorilla loves bananas and is given several piles of them. Each pile has a certain number of bananas, and Koko can eat at most k bananas per hour. Given a time limit h hours, the task is to determine the minimum eating…

The “Online Stock Span” problem involves calculating the stock span, which the number of consecutive days (including today) a stock’s price was less than or equal to its current price. For example, if the stock price today is higher than the last three days, the span is four. It’s like…

The problem Daily Temperatures asks you to analyze a list of daily temperatures and determine, for each day, how many days you need to wait to see a warmer temperature. If no warmer day exists in the future, the result for that day is 0. For example, given temperatures like…

The “String Compression” problem requires reducing the size of a character array by compressing consecutive repeating characters into a single character followed by their count. For example, the [“a”, “a”, “b”, “b”, “b”, “c”] should be compressed to [“a”, “2”, “b”, “3”, “c”]. The challenge is to perform this compression…

The Reverse Integer problem asks us to take an integer as input and return its digits reversed. For example, if the input is 123, the output should be 321. If the input is negative, like -123, the output should be -321. There is a constraint: if reversing the integer causes…

The Summary Ranges problem asks us to take a sorted list of integers and group consecutive numbers into ranges. For example, given the input [0, 1, 2, 4, 5, 7], the output would be [“0->2”, “4->5”, “7”]. The goal is to find and summarize sequences of consecutive numbers in a…