You are playing a game with a circular array where each element indicates how many steps to move forward or backward. Determine if there exists a cycle in the array where the cycle has more than one element and all elements in the cycle move in the same direction. Return true if such a cycle exists, otherwise return false.
You are given the positions of houses and heaters along a horizontal line. Your task is to find the minimum radius required for the heaters so that all houses are within the heater’s warm radius.
A magical string consists of only ‘1’ and ‘2’ and follows a special rule: the number of consecutive occurrences of characters ‘1’ and ‘2’ generates the string itself. Given an integer n, return the number of ‘1’s in the first n characters of the magical string.
Given an array of strings strs, determine the length of the longest uncommon subsequence between them. An uncommon subsequence is a string that is a subsequence of one string but not the others. If no such subsequence exists, return -1.
Given a string s and a string array dictionary, return the longest string from the dictionary that can be formed by deleting some characters of s. If there are multiple valid words, return the longest word with the smallest lexicographical order. If no valid word exists, return an empty string.
Given an array of integers nums and an integer k, return the number of unique k-diff pairs in the array. A k-diff pair is a pair of integers (nums[i], nums[j]) where the absolute difference between the values of the pair is k, and i != j.
