## Flatten Binary Tree to Linked List

Flatten a binary tree to a fake “linked list” in pre-order traversal.

## Swap Nodes in Pairs

Given a linked list, swap every two adjacent nodes and return its head.

## Subarray Sum to Zero

Given an integer array, find a subarray where the sum of numbers is zero. Your code should return the index of the first number and the index of the last number.

## Identical Binary Tree

Check if two binary trees are identical. Identical means the two binary trees have the same structure and every identical position has the same value.

## Binary Tree Paths

Given a binary tree, return all root-to-leaf paths.

## Happy Number

Write an algorithm to determine if a number is happy.

## Count Digits in an Integer

The following snippet uses `log()`

to find the number of digits in the integer `x`

. The result is 5.

## Least Significant Digits of Integer

Least significant digits of an integer can be obtained by performing modulo of power of 10. Note that modulo is the division remainder operator.

## Java Generics

Data structures and collections help us organize data in our program. For example, the `TreeSet`

class is a collection data structure that always keep the objects sorted, and the `Stack`

class always keep the last object added at the front. Both classes are data structures built into the Java standard library

## COMP2210 A2

The goal of this assignment is to perform searching operations (min, max, kmin, kmax) from a generic collection using a Comparator. The collection and Comparator are passed into the methods as ** c**, and

**.**

`comp`