Test point: decomposition makes complex problems simple
https://www.nowcoder.com/questionTerminal/f836b2c43afc4b35ad6adc41ec941dba?f=discussion
Title Description
Enter a complex linked list (each node has a node value, and two pointers, one to the next node, and another special pointer random to a random node). Please make a deep copy of this linked list and return the copied head node. (Note: please do not return the node reference in the parameter in the output result, otherwise the problem determination program will directly return null)
Solutions to problems
Link: https://www.nowcoder.com/questionTerminal/f836b2c43afc4b35ad6adc41ec941dba?f=discussion
Source: niuke.com
Source: niuke.com
/*
*Solutions:
*1. Traverse the list and copy each node. For example, copy node a to get A1, and insert node A1 after node a;
*2. Traverse the linked list again, copy the random pointer of the old node to the new node, such as A1.random = A.random.next;
*3. Split the linked list into the original one and the copied one
*/
/* public class RandomListNode { int label; RandomListNode next = null; RandomListNode random = null; RandomListNode(int label) { this.label = label; } } */ public class Solution { public RandomListNode Clone(RandomListNode pHead) { if(pHead == null) { return null; } RandomListNode currentNode = pHead; //1,Copy each node, such as a copy node A obtain A1，The node A1 Insert to node A Back; while(currentNode != null){ RandomListNode cloneNode = new RandomListNode(currentNode.label); RandomListNode nextNode = currentNode.next; currentNode.next = cloneNode; cloneNode.next = nextNode; currentNode = nextNode; } currentNode = pHead; //2,Traverse the linked list again, copy the random pointer of the old node to the new node, such as A1.random = A.random.next; while(currentNode != null) { currentNode.next.random = currentNode.random==null?null:currentNode.random.next; currentNode = currentNode.next.next; } //3,Split the linked list into the original one and the copied one currentNode = pHead; RandomListNode pCloneHead = pHead.next; while(currentNode != null) { RandomListNode cloneNode = currentNode.next; currentNode.next = cloneNode.next; cloneNode.next = cloneNode.next==null?null:cloneNode.next.next; currentNode = currentNode.next; } return pCloneHead; } }