Given an integer array nums and an integer k, return true if there exists a good subarray, otherwise return false. A good subarray is defined as a subarray whose length is at least 2 and the sum of its elements is a multiple of k.
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.
You are given a 0-indexed array of positive integers w, where w[i] describes the weight of the ith index. You need to implement the function pickIndex() which randomly picks an index in the range [0, w.length - 1] (inclusive), and the probability of picking index i is w[i] / sum(w).
You are playing the game Minesweeper. Given an m x n grid, you must reveal the square corresponding to the next click and update the grid according to Minesweeper’s rules. The grid can contain mines (‘M’), empty squares (‘E’), or revealed squares with adjacent mine counts.
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.
