链表是面试中最常见的一种题型，因为他的每个题的代码短，短短的几行代码就可以体现出应聘者的编码能力，所以它也就成为了面试的重点。
链表常见的操作有1.打印链表的公共部分，2.删除链表的倒数第K个节点，3.翻转单向链表，4.环形约瑟夫环问题，5.判断链表是否是一个回文链表，6.两个链表生成相加链表，7.删除无序链表中重复出现的节点，8.删除指定值得节点，9.合并两个有序的单链表，10.环形链表的插入
import java.util.*;
/**********
*@Author:Tom-shushu
*@Description:链表问题
*@Date:21:58 2019/10/2
* .--, .--,
* ( ( \.---./ ) )
* ‘.__/o o\__.‘
* {= ^ =}
* > - <
* / * // \ * //| . |\ * "‘\ /‘"_.-~^`‘-.
* \ _ /--‘ `
* ___)( )(___
* (((__) (__))) 高山仰止,景行行止.虽不能至,心向往之。
*
**********/
public class Node {
public int value;
public Node head;
public Node next;
public Node(int data) {
this.value = data;
}
//打印链表的公共部分
public void print(Node head1, Node head2) {
while (head1 != null && head2 != null) {
if (head1.value < head2.value) {
head1 = head1.next;
} else if (head1.value > head2.value) {
head2 = head2.next;
} else {
System.out.println(head1.value);
head1 = head1.next;
head2 = head2.next;
}
}
}
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//删除单链表的倒数第K个节点
//版本一
public Node remove1(Node head, int k) {
if (head == null || k < 1) {
return head;
}
Node cur = head;
while (cur != null) {
k--;
cur = cur.next;
}
if (k == 0) {//要删除的是第一个
head = head.next;
}
if (k < 0) {
cur = head;
while (++k != 0) {
cur = cur.next;
}
cur.next = cur.next.next;
}
return head;
}
//版本二
public Node remove2(Node head, int k) {
if (head == null || k <= 0) {
return null;
}
Node slow = head;
Node fast = head;
//fast 指向 k + 1
for (int i = 1; i < k + 1; i++) {
if (fast.next != null) {
fast = fast.next;
} else {
return null;
}
}
//fast指向尾部，slow指向倒数K+1，即 k 的前一个数。
while (fast.next != null) {
fast = fast.next;
slow = slow.next;
}
//删除第 k 个数。
slow = slow.next.next;
return head;
}
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//翻转单向链表
//版本一
public Node reList(Node head) {
Node pre = null;
Node next = null;
while (head != null) {
next = head.next;
head.next = pre;
pre = head;
head = next;
}
return pre;
}
//版本二
public Node reList2(Node head) {
if (head == null || head.next == null) {
return head;
}
Node pre = head;
Node newHead = null;
while (pre != null) {
Node temp = pre.next;
pre.next = newHead;
newHead = pre;
pre = temp;
}
return newHead;
}
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//环形约瑟夫问题
public Node yuesefu(Node head, int m) {
if (head == null || head.next == head || m < 1) {
return head;
}
Node last = head;
while (last.next != head) {
last = last.next;
}
int count = 0;
while (head != last) {
if (++count == m) {
last.next = head.next;
count = 0;
} else {
last = last.next;
}
head = last.next;
}
return head;
}
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//判断一个链表是否是回文链表
public boolean isHuiWen(Node head) {
Stack<Node> stack = new Stack<Node>();
Node cur = head;
while (cur != null) {
stack.push(cur);
cur = cur.next;
}
while (head != null) {
if (head.value != stack.pop().value) {
return false;
}
head = head.next;
}
return true;
}
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//两个单链表生成相加链表
public Node xinagjialainbiao(Node head1, Node head2) {
Stack<Integer> stack1 = new Stack<Integer>();
Stack<Integer> stack2 = new Stack<Integer>();
while (head1 != null) {
stack1.push(head1.value);
head1 = head1.next;
}
while (head2 != null) {
stack2.push(head1.value);
head2 = head2.next;
}
int ca = 0;
int n1 = 0;
int n2 = 0;
int n = 0;
Node node = null;
Node pre = null;
while (!stack1.isEmpty() || !stack2.isEmpty()) {
if (stack1.isEmpty()) {
n1 = 0;
} else {
n1 = stack1.pop();
}
if (stack2.isEmpty()) {
n2 = 0;
} else {
n2 = stack2.pop();
}
pre = node;
node = new Node(n % 10);
node.next = pre;
}
if (ca == 1) {
pre = node;
node = new Node(1);
node.next = pre;
}
return node;
}
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//删除无需单链表中重复出现的节点
public void deletecf(Node head) {
if (head == null) {
return;
}
HashSet<Integer> set = new HashSet<Integer>();
Node pre = head;
Node cur = head.next;
set.add(head.value);
while (cur != null) {
if (set.contains(cur.value)) {
pre.next = cur.next;
} else {
set.add(cur.value);
pre = cur;
}
cur = cur.next;
}
}
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//在单链表中删除指定值得节点
public Node deletevalue(Node head, int num) {
Stack<Node> stack = new Stack<Node>();
while (head != null) {
if (head.value != num) {
stack.push(head);
}
head = head.next;
}
while (!stack.isEmpty()) {
stack.peek().next = head;
head = stack.pop();
}
return head;
}
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//合并两个有序单链表(递归)
public Node Merge(Node list1, Node list2) {
if (list1 == null) {
return list2;
}
if (list2 == null) {
return list1;
}
if (list1.value <= list2.value) {
list1.next = Merge(list1.next, list2);
return list1;
} else {
list2.next = Merge(list1, list2.next);
return list2;
}
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++==
//环形链表的插入
public Node insertNum(Node head,int num){
Node node = new Node(num);
if(head == null){
node.next = node;
return node;
}
Node pre = head;
Node cur = head.next;
while (cur != head){
if (pre.value <= num && cur.value >= num){
break;
}
pre = cur;
cur = cur.next;
}
pre.next = node;
node.next = cur;
return head.value < num ? head : node;
}
}
原文地址：https://www.cnblogs.com/Tom-shushu/p/11622578.html
时间： 2024-11-09 00:35:29