## Number of Distinct Islands

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.) You may assume all four edges of the grid are surrounded by water.

## Number of Islands

Given a 2d grid map of ‘1’s (land) and ‘0’s (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by water.

## Delete Node from a BST

Given a root node reference of a BST and a key, delete the node with the given key from the BST. Return the root node reference (possibly updated) of the BST.

## Insert into a Binary Search Tree

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.

## Move Zeroes to the end of the array

Given an array nums, write a function to move all 0’s to the end of it while maintaining the relative order of the non-zero elements.

## Meeting Rooms II

Given an array of meeting time intervals intervals, return the minimum number of conference rooms required.

## All Nodes Distance K in Binary Tree

We are given a binary tree (with root node root), a target node, and an integer value K. Return a list of the values of all nodes that have a distance K from the target node.

## Letter Combinations of a Phone Number

Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent.

## Subsets II

Given an integer array nums that may contain duplicates, return all possible subsets (the power set). The solution set must not contain duplicate subsets. Return the solution in any order.

## Gnerate all possible subsets – Subsets

In mathematics, the power set of a set S is the set of all subsets of S, including the empty set and S itself.