From 1cc64d5c75ad283a21e762f764c4c4b0e5250bd1 Mon Sep 17 00:00:00 2001
From: algorithmzuo <algorithmzuo@163.com>
Date: Tue, 10 Aug 2021 19:15:16 +0800
Subject: [PATCH] modify code

---
 src/class09/Code04_CopyListWithRandom.java | 109 +++++----------------
 1 file changed, 24 insertions(+), 85 deletions(-)

diff --git a/src/class09/Code04_CopyListWithRandom.java b/src/class09/Code04_CopyListWithRandom.java
index 27ec73b..f42454f 100644
--- a/src/class09/Code04_CopyListWithRandom.java
+++ b/src/class09/Code04_CopyListWithRandom.java
@@ -2,25 +2,28 @@ package class09;
 
 import java.util.HashMap;
 
+// 测试链接 : https://leetcode.com/problems/copy-list-with-random-pointer/
 public class Code04_CopyListWithRandom {
 
 	public static class Node {
-		public int value;
-		public Node next;
-		public Node rand;
+		int val;
+		Node next;
+		Node random;
 
-		public Node(int data) {
-			this.value = data;
+		public Node(int val) {
+			this.val = val;
+			this.next = null;
+			this.random = null;
 		}
 	}
 
-	public static Node copyListWithRand1(Node head) {
+	public static Node copyRandomList1(Node head) {
 		// key 老节点
 		// value 新节点
 		HashMap<Node, Node> map = new HashMap<Node, Node>();
 		Node cur = head;
 		while (cur != null) {
-			map.put(cur, new Node(cur.value));
+			map.put(cur, new Node(cur.val));
 			cur = cur.next;
 		}
 		cur = head;
@@ -29,112 +32,48 @@ public class Code04_CopyListWithRandom {
 			// map.get(cur) 新
 			// 新.next ->  cur.next克隆节点找到
 			map.get(cur).next = map.get(cur.next);
-			map.get(cur).rand = map.get(cur.rand);
+			map.get(cur).random = map.get(cur.random);
 			cur = cur.next;
 		}
 		return map.get(head);
 	}
 
-	public static Node copyListWithRand2(Node head) {
+	public static Node copyRandomList2(Node head) {
 		if (head == null) {
 			return null;
 		}
 		Node cur = head;
 		Node next = null;
-		// copy node and link to every node
-		// 1 -> 2
-		// 1 -> 1' -> 2
+		// 1 -> 2 -> 3 -> null
+		// 1 -> 1' -> 2 -> 2' -> 3 -> 3'
 		while (cur != null) {
-			// cur 老 next 老的下一个
 			next = cur.next;
-			cur.next = new Node(cur.value);
+			cur.next = new Node(cur.val);
 			cur.next.next = next;
 			cur = next;
 		}
 		cur = head;
-		Node curCopy = null;
-		// set copy node rand
-		// 1 -> 1' -> 2 -> 2'
+		Node copy = null;
+		// 1 1' 2 2' 3 3'
+		// 依次设置 1' 2' 3' random指针
 		while (cur != null) {
-			// cur 老
-			// cur.next 新 copy
 			next = cur.next.next;
-			curCopy = cur.next;
-			curCopy.rand = cur.rand != null ? cur.rand.next : null;
+			copy = cur.next;
+			copy.random = cur.random != null ? cur.random.next : null;
 			cur = next;
 		}
-		// head head.next
 		Node res = head.next;
 		cur = head;
-		// split
+		// 老 新 混在一起，next方向上，random正确
+		// next方向上，把新老链表分离
 		while (cur != null) {
 			next = cur.next.next;
-			curCopy = cur.next;
+			copy = cur.next;
 			cur.next = next;
-			curCopy.next = next != null ? next.next : null;
+			copy.next = next != null ? next.next : null;
 			cur = next;
 		}
 		return res;
 	}
 
-	public static void printRandLinkedList(Node head) {
-		Node cur = head;
-		System.out.print("order: ");
-		while (cur != null) {
-			System.out.print(cur.value + " ");
-			cur = cur.next;
-		}
-		System.out.println();
-		cur = head;
-		System.out.print("rand:  ");
-		while (cur != null) {
-			System.out.print(cur.rand == null ? "- " : cur.rand.value + " ");
-			cur = cur.next;
-		}
-		System.out.println();
-	}
-
-	public static void main(String[] args) {
-		Node head = null;
-		Node res1 = null;
-		Node res2 = null;
-		printRandLinkedList(head);
-		res1 = copyListWithRand1(head);
-		printRandLinkedList(res1);
-		res2 = copyListWithRand2(head);
-		printRandLinkedList(res2);
-		printRandLinkedList(head);
-		System.out.println("=========================");
-
-		head = new Node(1);
-		head.next = new Node(2);
-		head.next.next = new Node(3);
-		head.next.next.next = new Node(4);
-		head.next.next.next.next = new Node(5);
-		head.next.next.next.next.next = new Node(6);
-
-		head.rand = head.next.next.next.next.next; // 1 -> 6
-		head.next.rand = head.next.next.next.next.next; // 2 -> 6
-		head.next.next.rand = head.next.next.next.next; // 3 -> 5
-		head.next.next.next.rand = head.next.next; // 4 -> 3
-		head.next.next.next.next.rand = null; // 5 -> null
-		head.next.next.next.next.next.rand = head.next.next.next; // 6 -> 4
-
-		System.out.println("原始链表：");
-		printRandLinkedList(head);
-		System.out.println("=========================");
-		res1 = copyListWithRand1(head);
-		System.out.println("方法一的拷贝链表：");
-		printRandLinkedList(res1);
-		System.out.println("=========================");
-		res2 = copyListWithRand2(head);
-		System.out.println("方法二的拷贝链表：");
-		printRandLinkedList(res2);
-		System.out.println("=========================");
-		System.out.println("经历方法二拷贝之后的原始链表：");
-		printRandLinkedList(head);
-		System.out.println("=========================");
-
-	}
-
 }