Description https://leetcode.com/problems/check-if-n-and-its-double-exist/ Given an array arr of integers, check if there exists two integers N and M such that N is the double of M ( i.e. N = 2 *…

Description https://leetcode.com/problems/add-to-array-form-of-integer/ The array-form of an integer num is an array representing its digits in left to right order. For example, for num = 1321,…

Description https://leetcode.com/problems/reverse-vowels-of-a-string/ Given a string s, reverse only all the vowels in the string and return it. The vowels are ‘a’, ‘e’, ‘i’, ‘o’, and ‘u’,…

Description https://leetcode.com/problems/range-sum-query-immutable/ Given an integer array nums, find the sum of the elements between indices left and right inclusive, where (left <= right). Implement the NumArray class: NumArray(int[]…

Description https://leetcode.com/problems/find-smallest-letter-greater-than-target/ Given a list of sorted characters letters containing only lowercase letters, and given a target letter target, find the smallest element…

Description https://leetcode.com/problems/find-pivot-index/ Given an array of integers nums, calculate the pivot index of this array. The pivot index is the index where the sum of…

Description https://leetcode.com/problems/remove-element/ Given an array nums and a value val, remove all instances of that value in-place and return the new length. Do not allocate…

Description https://leetcode.com/problems/array-transformation/ Given an initial array arr, every day you produce a new array using the array of the previous day.…

Description https://leetcode.com/problems/meeting-rooms/ Given an array of meeting time intervals where intervals[i] = [starti, endi], determine if a person could attend all meetings. Example…

Description https://leetcode.com/problems/kth-missing-positive-number/ Given an array arr of positive integers sorted in a strictly increasing order, and an integer k. Find the kth positive integer that is missing…