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Copy pathDsTest.java
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276 lines (235 loc) · 5.44 KB
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package ds;
import java.util.LinkedList;
import java.util.Stack;
import org.junit.jupiter.api.Test;
class DsTest {
class SinglyLinkedListNode {
int data;
SinglyLinkedListNode next;
public SinglyLinkedListNode(int data) {
this.data = data;
next = null;
}
public int getData() {
return data;
}
public void setData(int data) {
this.data = data;
}
public SinglyLinkedListNode getNext() {
return next;
}
public void setNext(SinglyLinkedListNode next) {
this.next = next;
}
}
class DoublyLinkedListNode {
int data;
DoublyLinkedListNode prev;
DoublyLinkedListNode next;
}
static void deleteNode(SinglyLinkedListNode node) {
node.data = node.next.data;
node.next = node.next.next; // what about NULL pointer
}
// IN: 1->2->3->4->5->NULL, m=2, n=4
// OUT: 1->4->3->2->5->NULL
static SinglyLinkedListNode reverseBetween(SinglyLinkedListNode head, int m, int n) {
return null;
}
static SinglyLinkedListNode reverse(SinglyLinkedListNode head) {
return null;
}
// merge sort (split it)
static SinglyLinkedListNode sortList(SinglyLinkedListNode head) {
return null;
}
// IN: 1->4->3->2->5->2->NULL, x=3
// OUT: 1->2->2->4->3->5
static SinglyLinkedListNode partitionList(SinglyLinkedListNode head, int x) {
return null;
}
// slow, fast --> reverse 2nd part, then compare the 2 list
static boolean isPalindrome(SinglyLinkedListNode head) {
return false;
}
// IN: 1->4->3->2->5->2->NULL, k=2
// OUT: 1->4->3->2 ->2
static SinglyLinkedListNode removeNthNodeFromEndOfList(SinglyLinkedListNode head, int k) {
return null;
}
// BST
static class Node {
int data;
Node left, right;
Node (int data) {
this.data = data;
}
// insert
void insert(int d)
{
if (d <= this.data) {
if (left == null) {
left = new Node(d);
} else {
left.insert(d);
}
} else {
if (right == null) {
right = new Node(d);
} else {
right.insert(d);
}
}
}
// contains
boolean contains(int d) {
if (d == this.data) {
return true;
} else if (d < this.data) {
if (left == null) {
return false;
} else {
return left.contains(d);
}
} else {
if (right == null) {
return false;
} else {
return right.contains(d);
}
}
}
// printInOrder
void printInOrder() {
if (left != null) {
left.printInOrder();
}
System.out.println(this.data);
if (right != null) {
right.printInOrder();
}
}
// printPreOrder
// printPostOrder
}
class BST {
Node root;
void insert(int d) {
if (root == null) root = new Node(d);
else root.insert(d);
}
boolean contains(int d) {
if (root != null) return root.contains(d);
return false;
}
void printInOrder() {
if (root != null) root.printInOrder();
System.out.println();
}
}
static void preOrderIt(Node root) {
if (root == null) {
return;
}
Stack<Node> s = new Stack();
s.push(root);
while (!s.isEmpty()) {
// print root
Node curNode = s.pop();
System.out.println(curNode.data + " ");
//push right
if (curNode.right != null) {
s.push(curNode.right);
}
// push left
if (curNode.left != null) {
s.push(curNode.left);
}
}
}
static void preOrder(Node root) {
if (root == null) return;
System.out.println(root.data + " ");
preOrder(root.left);
preOrder(root.right);
}
static void inOrder(Node root) {
if (root == null) return;
inOrder(root.left);
System.out.println(root.data + " ");
inOrder(root.right);
}
static Node insert(Node root, int d) {
if (root == null) {
return new Node(d);
} else {
Node cur;
if (d <= root.data) {
cur = insert(root.left, d);
root.left = cur;
} else {
cur = insert(root.right, d);
root.right = cur;
}
}
return root;
}
static void levelOrder(Node root) {
if (root == null) {
return;
}
LinkedList <Node> queue = new LinkedList();
queue.add(root);
while (!queue.isEmpty()) {
Node curNode = queue.poll();
System.out.println(curNode.data + " ");
// left
if (curNode.left != null) queue.add(curNode.left);
//right
if (curNode.right != null) queue.add(curNode.right);
}
}
static int getNodeFromTail( SinglyLinkedListNode head, int tailPos) {
// use head to do loop run
// use 2nd node runner to delay tailPos step to start
// when head run to the end, the delayed pointer is at the correct pos
SinglyLinkedListNode nodePointer = head;
int count = 0;
while (head != null ) {
head = head.next;
if (count < tailPos) {
count++;
} else {
nodePointer = nodePointer.next;
}
}
return nodePointer.getData();
}
static int findMergeNode(SinglyLinkedListNode head1, SinglyLinkedListNode head2) {
// 1: 1 -> 2 -> 3 -> 7 -> 8
// 2: 5 -> 6 -> 7 -> 8
// 1: 1 -> 2 -> 3 -> 7 -> 8 -> 5 -> 6 -> 7 -> 8 (length 9)
// 2: 5 -> 6 -> 7 -> 8 -> 1 -> 2 -> 3 -> 7 -> 8 (length 9)
SinglyLinkedListNode head1_current = head1;
SinglyLinkedListNode head2_current = head2;
while (head1_current != head2_current) {
if (head1_current == null) {
head1_current = head2;
} else {
head1_current = head1_current.next;
}
if (head2_current == null) {
head2_current = head1;
} else {
head2_current = head2_current.next;
}
}
return head1_current.getData();
}
@Test
void testGetNodeFromTail() {
// 1 -> 2 -> 3 -> 4 -> 5 -> 6 -> 7 -> 8 -> 9 -> 10
// tail position: 3 => result: 7
}
}