Problem Statement Find the Duplicate Number LeetCode Solution – Given an array of integers nums containing n + 1 integers where each integer is in the range [1, n] inclusive. There is only one repeated number in nums, return this repeated number. You must solve the problem without modifying the array nums and uses only constant extra space. Input: nums = [1,3,4,2,2] Output: 2 Explanation …
Problem Statement Snakes and Ladders LeetCode Solution – You are given an n x n integer matrix board where the cells are labeled from 1 to n2 in a Boustrophedon style starting from the bottom left of the board (i.e. board[n – 1][0]) and alternating directions in each row. You start on the square 1 of the board. In each move, …
Problem Statement : Arithmetic Slices II – Subsequence LeetCode Solution – Given an integer array of nums, return the number of all the arithmetic subsequences of nums. A sequence of numbers is called arithmetic if it consists of at least three elements and if the difference between any two consecutive elements is the same. For …
Problem Statement: Missing Element in Sorted Array LeetCode Solution – Given an integer array nums which are sorted in ascending order and all of its elements are unique and given also an integer k, return the kth missing number starting from the leftmost number of the array. Example: Example 1 Input: nums = [4,7,9,10], k = …
Problem Statement : Path Sum II LeetCode Solution – Given the root of a binary tree and an integer targetSum, return all root-to-leaf paths where the sum of the node values in the path equals targetSum. Each path should be returned as a list of the node values, not node references. A root-to-leaf path is a path starting from …
Problem Statement Flatten 2D Vector LeetCode Solution – Design an iterator to flatten a 2D vector. It should support the next and hasNext operations. Implement the Vector2D class: Vector2D(int[][] vec) initializes the object with the 2D vector vec. next() returns the next element from the 2D vector and moves the pointer one step forward. You may assume that all …
Problem Statement Alien Dictionary LeetCode Solution – There is a new alien language that uses the English alphabet. However, the order among the letters is unknown to you. You are given a list of strings words from the alien language’s dictionary, where the strings in words are sorted lexicographically by the rules of this new language. …
Problem Statement Product of Array Except Self LeetCode Solution – Given an integer array nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i]. The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer. You must write an algorithm that runs in O(n) time and without using the division …
Problem Statement Design Skiplist LeetCode Solution – Design a Skiplist without using any built-in libraries. A skip list is a data structure that takes O(log(n)) time to add, erase and search. Compared with the tree and red-black tree which has the same function and performance, the code length of Skiplist can be comparatively …
Problem Statement Palindrome Permutation LeetCode Solution – We are given a string and asked if a permutation of the given string could form a palindrome. Examples & Explanations Example 1: Input: s = "code" Output: false Explanation: we can not arrange letters of "code" to form a palindrome Example 2: …