Leetcode Solutions

Question You’re given strings jewels representing the types of stones that are jewels, and stones representing the stones you have. Each character in stones is a type of stone you have. You want to know how many of the stones you have are also jewels. Letters are case sensitive, so “a” is considered a different type of stone from “A”. Example 1: Input: jewels […]

Question Given an m x n matrix, return true if the matrix is Toeplitz. Otherwise, return false. A matrix is Toeplitz if every diagonal from top-left to bottom-right has the same elements. Example 1: Input: matrix = [[1,2,3,4],[5,1,2,3],[9,5,1,2]] Output: true Explanation: In the above grid, the diagonals are: “[9]”, “[5, 5]”, “[1, 1, 1]”, “[2, 2, 2]”, “[3, 3]”, “[4]”. In each diagonal

Question You are given an integer array cost where cost[i] is the cost of ith step on a staircase. Once you pay the cost, you can either climb one or two steps. You can either start from the step with index 0, or the step with index 1. Return the minimum cost to reach the top of the floor. Example 1: Input: cost =

Question Given a characters array letters that is sorted in non-decreasing order and a character target, return the smallest character in the array that is larger than target. Note that the letters wrap around. For example, if target == ‘z’ and letters == [‘a’, ‘b’], the answer is ‘a’. Example 1: Input: letters = [“c”,”f”,”j”], target = “a” Output: “c” Example 2: Input: letters = [“c”,”f”,”j”], target

Question Given an array of integers temperatures represents the daily temperatures, return an array answer such that answer[i] is the number of days you have to wait after the ith day to get a warmer temperature. If there is no future day for which this is possible, keep answer[i] == 0 instead. Example 1: Input: temperatures = [73,74,75,71,69,72,76,73] Output: [1,1,4,2,1,1,0,0] Example 2: Input: temperatures = [30,40,50,60]

Question A self-dividing number is a number that is divisible by every digit it contains. For example, 128 is a self-dividing number because 128 % 1 == 0, 128 % 2 == 0, and 128 % 8 == 0. A self-dividing number is not allowed to contain the digit zero. Given two integers left and right, return a list of all the self-dividing numbers in the range [left, right]. Example 1: Input: left

Question Given a string s, return the string after replacing every uppercase letter with the same lowercase letter. Example 1: Input: s = “Hello” Output: “hello” Example 2: Input: s = “here” Output: “here” Example 3: Input: s = “LOVELY” Output: “lovely” Constraints: 1 <= s.length <= 100 s consists of printable ASCII characters. Python Solution

Question Given an array of integers nums which is sorted in ascending order, and an integer target, write a function to search target in nums. If target exists, then return its index. Otherwise, return -1. You must write an algorithm with O(log n) runtime complexity. Example 1: Input: nums = [-1,0,3,5,9,12], target = 9 Output: 4 Explanation: 9 exists in nums and its index is 4

Question Design a class to find the kth largest element in a stream. Note that it is the kth largest element in the sorted order, not the kth distinct element. Implement KthLargest class: KthLargest(int k, int[] nums) Initializes the object with the integer k and the stream of integers nums. int add(int val) Appends the integer val to the stream and returns the element representing the kth largest element in the stream.

Question You are given the root node of a binary search tree (BST) and a value to insert into the tree. Return the root node of the BST after the insertion. It is guaranteed that the new value does not exist in the original BST. Notice that there may exist multiple valid ways for the insertion, as long as the tree remains a BST after