Given a non-negative integer numRows, generate the first numRows of Pascal’s triangle. In Pascal’s triangle, each number is the sum of the two number ...

Given the root node of a binary search tree (BST) and a value. You need to find the node in the BST that the node’s value equals the given value. Retu ...

Given the root node of a binary search tree (BST) and a value to be inserted into the tree, insert the value into the BST. Return the root node of the ...

Given a positive integer, return its corresponding column title as appear in an Excel sheet. For example: 1 -> A 2 -> B 3 -> C ... 26 -> Z ...

Given a column title as appear in an Excel sheet, return its corresponding column number. For example: A -> 1 B -> 2 C -> 3 ... Z -> 26 AA ...

Given a non-empty 2D array grid of 0’s and 1’s, an island is a group of 1’s (representing land) connected 4-directionally (horizontal or vertical). Yo ...

In the following, every capital letter represents some hexadecimal digit from 0 to f. The red-green-blue color “#AABBCC” can be written as “#ABC” in s ...

Given an array with n objects colored red, white or blue, sort them in-place so that objects of the same color are adjacent, with the colors in the or ...

Given an array A of non-negative integers, half of the integers in A are odd, and half of the integers are even. Sort the array so that whenever A[i] ...

Given an unsorted array nums, reorder it such that nums[0] < nums[1] > nums[2] < nums[3]…. ExampleNo.1Input: nums = [1, 5, 1, 1, 6, 4] Output ...