Question You are given an alphanumeric string s. (Alphanumeric string is a string consisting of lowercase English letters and digits). You have to find a permutation of the string where no letter is followed by another letter and no digit is followed by another digit. That is, no two adjacent characters have the same type. Return the reformatted […]

Question Given an integer k, return the minimum number of Fibonacci numbers whose sum is equal to k. The same Fibonacci number can be used multiple times. The Fibonacci numbers are defined as: F1 = 1 F2 = 1 Fn = Fn-1 + Fn-2 for n > 2. It is guaranteed that for the given constraints we can always find such Fibonacci numbers that

Question Given an array of integers nums, you start with an initial positive value startValue. In each iteration, you calculate the step by step sum of startValue plus elements in nums (from left to right). Return the minimum positive value of startValue such that the step by step sum is never less than 1. Example 1: Input: nums = [-3,2,-3,4,2] Output: 5 Explanation: If you choose startValue =

Question Given an array of string words. Return all strings in words which is substring of another word in any order.  String words[i] is substring of words[j], if can be obtained removing some characters to left and/or right side of words[j]. Example 1: Input: words = [“mass”,”as”,”hero”,”superhero”] Output: [“as”,”hero”] Explanation: “as” is substring of “mass” and “hero” is substring of “superhero”. [“hero”,”as”] is also a valid

Question Given an array of integers arr, a lucky integer is an integer that has a frequency in the array equal to its value. Return the largest lucky integer in the array. If there is no lucky integer return -1. Example 1: Input: arr = [2,2,3,4] Output: 2 Explanation: The only lucky number in the array is 2 because frequency[2] == 2. Example 2:

Question Given two arrays of integers nums and index. Your task is to create target array under the following rules: Initially target array is empty. From left to right read nums[i] and index[i], insert at index index[i] the value nums[i] in target array. Repeat the previous step until there are no elements to read in nums and index. Return the target array. It is guaranteed that the insertion operations will be valid. Example

Question The power of an integer x is defined as the number of steps needed to transform x into 1 using the following steps: if x is even then x = x / 2 if x is odd then x = 3 * x + 1 For example, the power of x = 3 is 7 because 3 needs 7 steps to become 1 (3 –> 10 –> 5 –> 16 –> 8 –> 4 –> 2

Question Given two integer arrays arr1 and arr2, and the integer d, return the distance value between the two arrays. The distance value is defined as the number of elements arr1[i] such that there is not any element arr2[j] where |arr1[i]-arr2[j]| <= d. Example 1: Input: arr1 = [4,5,8], arr2 = [10,9,1,8], d = 2 Output: 2 Explanation: For arr1[0]=4 we have: |4-10|=6 > d=2

Question Given an m x n matrix of distinct numbers, return all lucky numbers in the matrix in any order. A lucky number is an element of the matrix such that it is the minimum element in its row and maximum in its column. Example 1: Input: matrix = [[3,7,8],[9,11,13],[15,16,17]] Output: [15] Explanation: 15 is the only lucky number since it is the minimum in its

Question Given two binary trees original and cloned and given a reference to a node target in the original tree. The cloned tree is a copy of the original tree. Return a reference to the same node in the cloned tree. Note that you are not allowed to change any of the two trees or the target node and the answer must be a reference to a node in the cloned tree. Example 1: Input: tree = [7,4,3,null,null,6,19], target =