kolauren

# Not really a "use-case" per se, but I always thought this problem was 
# interesting because it has a really simple answer (as you can see below).
# Sometimes it is asked in coding interviews.
#
# How do you implement a Queue using only Stack data structure?

class Node:
  def __init__(self, item, next):
		self.item = item
		self.next = next

kolauren

# A simple stack, LIFO fo' lyfe

class Node:
  def __init__(self, item, next):
		self.item = item
		self.next = next
	

class Stack: 
	top = None

kolauren

// Heapsort with Java

// Heap properties:
// Left child of h[i] is h[2i + 1] (given 2i + 1 < h.size)
// Right child of h[i] is h[2i + 2] (given 2i + 2 < h.size)
// parent of h[i] is h[(i-1)/2] (given i > 0)

public class Heap {
    int[] heap;
	int size;

kolauren

// Reverse a linked list
public class Test {
  
	public static class Node {
		public int value;
		public Node next;
		public Node(int value, Node next) {
			this.value = value;
			this.next = next;
		}

kolauren

import java.util.*;
public class Test {
  
	// You are given an array with n positive integers where all values in the array are repeated except for one. 
	// Return the one that is not repeated.   

	// brute force answer
	public static int notRepeated_bf(int[] integers) {
		int not_repeated;
		int current_num;

kolauren

1. Explain what the big three depth-first tree traversals are and what to consider when implementing them.

The big three depth-first tree traversals are ways to traverse a tree. "Depth-first" means that they will traverse to the lowest depth before moving on to the next node. The three ways are inorder (left, root, right), preorder (root, left, right) and postorder (left, right, root).