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‎Common/src/classes/ListNode.java

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package classes;
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import java.util.ArrayList;
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import java.util.List;
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import utils.CommonUtils;
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/**
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* Normally, both val and next should be private attributes and generate getter and setter for them,
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* but for the convenience of leetcode solutions, I set them as public.
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*/
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public class ListNode {
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public int val;
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public ListNode next;
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public ListNode(int i) {
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this.val = i;
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}
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public int val() {
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return val;
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}
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public static ListNode createSinglyLinkedList() {
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ListNode head = new ListNode(1);
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ListNode node1 = new ListNode(2);
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head.next = node1;
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ListNode node2 = new ListNode(3);
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node1.next = node2;
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ListNode node3 = new ListNode(4);
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node2.next = node3;
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ListNode node4 = new ListNode(5);
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node3.next = node4;
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ListNode node5 = new ListNode(6);
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node4.next = node5;
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ListNode node6 = new ListNode(7);
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node5.next = node6;
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ListNode node7 = new ListNode(8);
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node6.next = node7;
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ListNode node8 = new ListNode(9);
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node7.next = node8;
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ListNode node9 = new ListNode(10);
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node8.next = node9;
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return head;
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}
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/**TODO: this function is NOT working as supposed to, I need to fix it!*/
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public static ListNode createSinglyLinkedList(List<Integer> listValues) {
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if (listValues == null || listValues.size() == 0)
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throw new IllegalArgumentException(
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"Please pass in a valid listValues to create a singly linked list.");
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ListNode head = new ListNode(listValues.get(0));
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for(int i : listValues){
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appendNode(head, i);
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}
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printList(head);
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return head;
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}
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private static void appendNode(ListNode head, int i) {
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ListNode node = new ListNode(i);
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head.next = node;
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// head = head.next;
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}
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public static void printList(ListNode head) {
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ListNode temp = head;
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System.out.println();
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while (temp != null) {
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System.out.print(temp.val() + "\t");
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temp = temp.next;
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}
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}
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public static void main(String...strings){
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List<Integer> values = CommonUtils.randomIntArrayGenerator(10, 20);
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createSinglyLinkedList(values);
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ListNode head = createSinglyLinkedList();
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printList(head);
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System.out.println("The end.");
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}
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}

‎Common/src/utils/CommonUtils.java

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package utils;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.Random;
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import classes.ListNode;
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public class CommonUtils {
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private static final int DEFAULT_TREE_SIZE = 10;
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private static final int DEFAULT_UPPER_BOUND = 100;
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public static void print(String message) {
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System.out.print(message);
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}
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public static void print(int num) {
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System.out.print(num);
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}
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public static void println(String message) {
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System.out.println(message);
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}
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public static void println(int num) {
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System.out.println(num);
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}
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public static void println() {
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System.out.println();
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}
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//overloaded method to take only one argument
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public static List<Integer> randomIntArrayGenerator(int size) {
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return CommonUtils.randomIntArrayGenerator(size, DEFAULT_UPPER_BOUND);
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}
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//overloaded method to take no argument
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public static List<Integer> randomIntArrayGenerator() {
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return CommonUtils.randomIntArrayGenerator(CommonUtils.DEFAULT_TREE_SIZE, DEFAULT_UPPER_BOUND);
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}
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//this one has two other overloaded methods as above
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public static List<Integer> randomIntArrayGenerator(int size, int upperBound) {
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List<Integer> result = new ArrayList<Integer>();
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Random random = new Random();
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for (int i = 0; i < size; i++) {
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int randomInt = random.nextInt(upperBound);
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result.add(randomInt);
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print(String.valueOf(randomInt) + " ");
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}
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println();
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return result;
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}
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//this one has two other overloaded methods as above
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public static List<Integer> uniqueIntArrayGenerator(int size) {
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List<Integer> result = new ArrayList<Integer>();
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for (int i = 0; i < size; i++) {
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result.add(i);
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}
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println();
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return result;
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}
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// @Notes(context = "I'm assuing only classes in this PACKAGE will call the following two methods, so just leave the modifier as default, i.e. no public, private, or protected.")
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public
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static void printWhitespaces(int count) {
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for (int i = 0; i < count; i++)
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System.out.print(" ");
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}
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public static <T> boolean isAllElementsNull(List<T> list) {
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for (Object object : list) {
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if (object != null)
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return false;
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}
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return true;
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}
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/**
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* If you want to print the reversed list out, you need to return the
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* reversed list's head, which was the end node of the original node. using
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* the following function.
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*/
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public static ListNode reverseList(ListNode head) {
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if (head == null || head.next == null) {
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return head;
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}
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ListNode previous, current, next;
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previous = head;
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current = head.next;
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while (current != null) {
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next = current.next;
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current.next = previous;
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previous = current;
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current = next;
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}
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head.next = null;
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return previous;
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}
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public static void printList(ListNode head) {
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System.out.println("--------------------------------------------");
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while (head != null) {
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System.out.print(head.val);
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head = head.next;
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}
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System.out.println();
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}
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}

‎RandomProblems/src/InterviewQuestions/FindLongestSuffixInTwoLists.java

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package InterviewQuestions;
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import classes.ListNode;
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/**Pinterest onsite question:
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* find the longest suffix in two linked lists
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* */
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public class FindLongestSuffixInTwoLists {
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public ListNode findLongestSuffix(ListNode head1, ListNode head2){
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}
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public static void main(String...strings){
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}
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}

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