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Copy pathNodeList.java
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414 lines (324 loc) · 8.13 KB
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import java.util.HashMap;
public class NodeList{
public class Node{
public int data;
public Node next;
}
private Node tail=null;
public Node CreateLinkListHead(){
Node head = new Node();
head.data=0;
head.next = null;
tail = head;
return head;
}
public Node getNode(int data){
Node node = new Node();
node.data=data;
node.next = null;
return node;
}
public void insertNode(Node head,Node node,int type){
//头插法
if(type == 0){
Node p = head.next;
head.next = node;
node.next = p;
//尾插法
}else{
Node p = head;
Node q = head;
while(p != null){
q=p;
p = p.next;
}
q.next = node;
}
}
public void printList(Node head){
Node p = head;
while(p != null){
System.out.print(p.data+",");
p = p.next;
}
}
public Node getLoopLinkList(){
NodeList list = new NodeList();
Node head = list.CreateLinkListHead();
list.insertNode(head,list.getNode(2),1);
Node loop = list.getNode(23);
list.insertNode(head,loop,1);
list.insertNode(head,list.getNode(25),1);
list.insertNode(head,loop,1);
return head;
}
public int getRandom(){
return (int)(Math.random()*9999);
}
public Node getNoLoopRandomLinkList(int length){
NodeList list = new NodeList();
Node head = list.CreateLinkListHead();
for (int i=0;i<length ;i++ ) {
list.insertNode(head,list.getNode(list.getRandom()),1);
}
return head;
}
public Node getNoLoopLinkList(){
NodeList list = new NodeList();
Node head = list.CreateLinkListHead();
list.insertNode(head,list.getNode(2),1);
list.insertNode(head,list.getNode(6),1);
list.insertNode(head,list.getNode(18),1);
list.insertNode(head,list.getNode(33),1);
list.insertNode(head,list.getNode(59),1);
list.insertNode(head,list.getNode(200),1);
return head;
}
public Node getNoLoopLinkList2(){
NodeList list = new NodeList();
Node head = list.CreateLinkListHead();
list.insertNode(head,list.getNode(1),1);
list.insertNode(head,list.getNode(16),1);
list.insertNode(head,list.getNode(38),1);
list.insertNode(head,list.getNode(63),1);
list.insertNode(head,list.getNode(99),1);
list.insertNode(head,list.getNode(190),1);
return head;
}
public Node getCrossingTwoLinkList(Node head1){
NodeList list = new NodeList();
Node head2 = list.CreateLinkListHead();
list.insertNode(head2,list.getNode(2),1);
list.insertNode(head2,list.getNode(21),1);
list.insertNode(head2,list.getNode(22),1);
Node loop = list.getNode(23);
list.insertNode(head2,loop,1);
list.insertNode(head2,list.getNode(24),1);
list.insertNode(head2,list.getNode(25),1);
list.insertNode(head1,list.getNode(3),1);
list.insertNode(head1,list.getNode(31),1);
list.insertNode(head1,list.getNode(32),1);
list.insertNode(head1,loop,1);
return head2;
}
//获取链表中成环的第一个节点
public Node getCycleNode(Node head){
if(head == null || head.next == null || head.next.next == null)
return null;
Node n1 = head.next;
Node n2 = head.next.next;
while(n1!= n2){
if(n1 == null || n2 == null)
return null;
n1 = n1.next;
n2 = n2.next.next;
}
n2 = head;
while(n1!=n2){
n1 = n1.next;
n2 = n2.next;
}
return n1;
}
//判断链表是否有环
//这个方法只能判断是否有环，不能找到入环的第一个节点
public Boolean hasCycle(Node head){
if(head == null || head.next == null)
return false;
Node slow = head;
Node fast = head.next;
while(slow != fast){
if(slow == null || fast == null)
return false;
slow = slow.next;
fast = fast.next.next;
}
return true;
}
//反转链表
public Node reverse(Node head){
Node prev = null;
Node curr = head;
while(curr!=null){
Node next = curr.next;
curr.next = prev;
prev = curr;
curr = next;
}
return prev;
}
//两链表是否相交的HashMap解法
public Boolean isCrossingByMashMap(Node head1,Node head2){
HashMap<Node,Integer> map = new HashMap<Node,Integer>();
Node curr=head1;
while(curr!=null){
map.put(curr,1);
curr = curr.next;
}
curr = head2;
while(curr!=null){
if(map.containsKey(curr)){
return true;
}
curr = curr.next;
}
return false;
}
//两链表是否相交的双指针解法
public Node isCrossing(Node head1,Node head2){
Node curr1=head1;
Node curr2=head2;
//这里包含了两种场景：
//1、两个链表都到了最后节点，表示没有相交，都为null，直接返回
//2、两个链表指向同一个节点，表示相交，返回任意一个即可
while(curr1 != curr2){
if(curr1 == null){
curr1=head2;
}else{
curr1 = curr1.next;
}
if(curr2 == null){
curr2=head1;
}else{
curr2 = curr2.next;
}
//因此，这里不需要写
// if(curr1 == curr2 && curr1 != null && curr2 != null)
// 来判断是否已经找到相交节点
}
return curr1;
}
//合并两个有序链表，返回新有序链表的头节点
public Node mergeTwoLists(Node head1,Node head2){
NodeList list = new NodeList();
Node head = list.CreateLinkListHead();
Node curr1 = head1;
Node curr2 = head2;
Node curr = head;
while(curr1 != null && curr2 != null){
Node n = null;
if(curr1.data > curr2.data){
n = list.getNode(curr2.data);
curr2 = curr2.next;
}else{
n = list.getNode(curr1.data);
curr1 = curr1.next;
}
list.insertNode(curr,n,1);
}
if(curr1 == null){
while(curr2!=null){
Node n = list.getNode(curr2.data);
list.insertNode(curr,n,1);
curr2 = curr2.next;
}
}
if(curr2 == null){
while(curr1!=null){
Node n = list.getNode(curr1.data);
list.insertNode(curr,n,1);
curr1 = curr1.next;
}
}
return head;
}
//查找链表倒数第K个元素
public Node findKth(Node head, int k){
int th = k;
int length = 0;
Node h = head;
while(h!=null){
length++;
th --;
h = h.next;
}
if(th>0) return null;
h = head;
Node p = null;
int index = length - k;
while(index>=0){
p = h;
h = h.next;
index--;
}
return p;
}
//查找链表倒数第K个元素
//优化版本
public Node findKth2(Node head,int k){
Node p = head;
Node q = head;
while(--k !=0 && p!=null){
p = p.next;
}
if(p == null) return null;
while(p.next!=null){
p = p.next;
q = q.next;
}
return q;
}
//删除某个链表中给定的（非末尾）节点
public void delete(Node node){
Node next = node.next;
node.data = next.data;
node.next = next.next;
}
//给定一个单链表，把所有的奇数节点和偶数节点分别排在一起
public void oddEvenList(Node head){
Node odd = head;
Node odd_end = null;
Node even = head.next;
while(odd != null && even != null){
Node t_odd = even.next;
Node t_even = t_odd.next;
odd.next = t_odd;
even.next = t_even;
odd = t_odd;
even = t_even;
odd_end = odd;
}
odd_end.next = head.next;
}
public static void _reverse(NodeList list){
Node head = list.getNoLoopLinkList();
head=list.reverse(head);
list.printList(head);
System.out.println("----------- _reverse end");
}
public static void _cross(NodeList list){
Node head1 = list.CreateLinkListHead();
Node head2 = list.getCrossingTwoLinkList(head1);
Node cross = list.isCrossing(head1,head2);
System.out.println("----------- _cross end");
System.out.print(cross!=null ? cross.data:null);
}
public static void _cycle(NodeList list){
Node head = list.getLoopLinkList();
Node node = list.getCycleNode(head);
System.out.println(node == null ?"No cycle node":node.data);
System.out.println("----------- _cycle end");
}
public static void _merge(NodeList list){
Node h1 = list.getNoLoopLinkList();
list.printList(h1);
System.out.println("----------- h1 end");
Node h2 = list.getNoLoopLinkList2();
list.printList(h2);
System.out.println("----------- h2 end");
Node h = list.mergeTwoLists(h1,h2);
list.printList(h);
System.out.println("----------- _merge end");
}
public static void _findKth(NodeList list){
Node h = list.getNoLoopLinkList();
list.printList(h);
System.out.println("----------- h end");
list.oddEvenList(h);
list.printList(h);
}
public static void main(String[] args){
NodeList list = new NodeList();
_findKth(list);
}
}