You are given an array nums of n + 1 integers where each integer is in the range [1, n]. The array contains exactly one duplicate number. Find and return this duplicate number without modifying the array and using constant extra space.
You are given a list of characters s. Your task is to reverse the order of characters in the list in-place, modifying the input list directly and without using any extra memory.
Given two integer arrays nums1 and nums2, return an array of their intersection. Each element in the result must be unique, and you may return the result in any order.
Given two strings s and t, return true if s is a subsequence of t, or false otherwise. A subsequence is formed by deleting some characters of t while maintaining the relative order of the remaining characters.
Given an array of characters, compress it by replacing consecutive repeating characters with the character followed by the count of repetitions. If the character repeats only once, just include the character. The result should modify the input array and return the new length of the array.
You are a parent with several children and a set of cookies. Each child has a greed factor, which is the minimum size of a cookie they will be happy with. Each cookie also has a size. Your task is to distribute the cookies such that you maximize the number of content children. Each child can receive at most one cookie, and each cookie can only be given to one child.
