DescriptionGiven two numbers represented as strings, return multiplication of the numbers as a string. Note: The numbers can be arbitrarily large and are non-negative. The original problem is here. Th

DescriptionGiven an unsorted integer array, find the first missing positive integer. For example,Given [1,2,0] return 3,and [3,4,-1,1] return 2. Your algorithm should run in O(n) time and uses constan

DescriptionGiven n points on a 2D plane, find the maximum number of points that lie on the same straight line. The original problem is here. The original code is here.

DescriptionGiven an integer array of size n, find all elements that appear more than ⌊ n/3 ⌋ times. The algorithm should run in linear time and in O(1) space. The original problem is here. The origina

DescriptionThere are N children standing in a line. Each child is assigned a rating value. You are giving candies to these children subjected to the following requirements: Each child must have at le

DescriptionGiven a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between tw

DescriptionGiven a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains only nodes with keys less than the node’s

DescriptionFind the total area covered by two rectilinear rectangles in a 2D plane. Each rectangle is defined by its bottom left corner and top right corner as shown in the figure. The original proble

DescriptionGiven a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list. For example,Given 1->2->3->3->4->4->5, retu

DescriptionGiven a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999. The original problem is here. The original code is here.