138 Copy List with Random Pointer
阿新 • • 發佈:2017-07-23
div fin put sin logs con 難點 spa rand
A linked list is given such that each node contains an additional random pointer
which could point to any node in the list or null. Return a deep copy of the list.
copy 的題多用hashmap, 難點在於如何讓遍歷, 如何構建新的節點間的關系.
/** * Definition for singly-linked list with a random pointer. * class RandomListNode { * int label; * RandomListNode next, random; * RandomListNode(int x) { this.label = x; } * }; */ public class Solution { public RandomListNode copyRandomList(RandomListNode head) { // write your code here HashMap<RandomListNode, RandomListNode> map = new HashMap<RandomListNode, RandomListNode>(); RandomListNode cur = head; while (cur != null) { RandomListNode copy = new RandomListNode(cur.label); map.put(cur, copy); cur = cur.next; } cur = head; while (cur != null) { map.get(cur).next = map.get(cur.next); map.get(cur).random = map.get(cur.random); cur = cur.next; } return map.get(head); } }
138 Copy List with Random Pointer