基础数据结构--链表的练习算法-数据结构java

一、单链表和双链表反转

public class ReverseNode {public static class Node { public int value; public Node next; public Node(int value) { this.value = https://www.it610.com/article/value; } }public static class DoubleNode { public int value; public DoubleNode last; public DoubleNode next; public DoubleNode(int value) { this.value = value; } }/** * 单链表反转 * a->b->c->null * c->b->a->null * * @return 返回头节点 */ public static Node reverseNode(Node head) { Node pre = null; Node next = null; while (head != null) { next = head.next; head.next = pre; pre = head; head = next; } return pre; }public static DoubleNode reverseDoubleNode(DoubleNode head) { DoubleNode pre = null; DoubleNode next = null; while (head != null) { next = head.next; head.next = pre; head.last = next; pre = head; head = next; }return pre; }}

核心点：
（1）单链表：
拿到next节点，修改当前节点的next节点，拿到pre节点，当前节点后移
（2）双链表：
拿到next节点，修改当前节点的next、last节点，拿到pre节点，当前节点后移
二、单链表删除指定的值

public class DeleteNodeValue {public static class Node { public int value; public Node next; public Node(int value) { this.value = https://www.it610.com/article/value; } }public static Node removeValue(Node head, int num) { while (head != null) { if (head.value != num) { break; } head = head.next; }Node pre = head; Node cur = head; while (cur != null) { if (cur.value == num) { pre.next = cur.next; } else { pre = cur; } cur = cur.next; }return head; }}

核心点：
1）找到不需要删除值的节点作为头节点（最后返回此头节点）
2）标记pre和cur节点
3）从cur开始挨个遍历剩下的节点
如果cur节点的值等于要删除的值，则修改pre节点的next节点；
【基础数据结构--链表的练习】如果cur节点的值不是要删除的值，则将pre节点修改为cur节点。