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在使用以下方法时需要定义一个LinkNode类来定义变量,new一个新对象进行调用,输出时需要定义输出方法
public class ListNode {int value;ListNode next;//public ListNode(int value) {this.value = value;}public String toString(){return "ListNode [value=" + value+", next="+next+"]";}public String toString1(){return "ListNode [value=" + value+"]";}
}
定义下面方法时需要提前定义头指针
public ListNode head = null;//定义头指针
1.插入,尾插法
//插入,尾插法public void insert(int value){ListNode node = new ListNode(value);if(head==null){head=node;return;}ListNode index = head;while (index.next!=null){index = index.next;}index.next=node;}
2.插入,头插法
//插入,头插法public void headinsert(int value){ListNode node = new ListNode(value);if(head==null){head=node;return;}node.next=head;head=node;}
3.输出链表上的值
//输出链表上的值public void printLink1(){ListNode index = head;while (index.next!=null){//最后一个value不进入循环System.out.print(index.value+" ");index = index.next;}System.out.println(index.value);}//输出链表上的值public void printLink2(){ListNode index = head;while (index!=null) {//最后一个value进入循环System.out.print(index.value+" ");index = index.next;}}
4.输出链表长度
//输出链表长度public int getListLength(){int temp=0;ListNode index = head;while (index!=null){temp++;index =index.next;}return temp;}
5.查找某个元素是否在链表上
//查找某个元素是否在链表上public boolean contains(int a){boolean b= false;ListNode index =head;if (head==null){b = false;}while (index!=null){if (index.value == a){b= true;}else {b=false;}index =index.next;}return b;}
6.任意位置插入
//任意位置插入public void addNodeAtIndex(int value,int position){//判断插入位置是否合法if(position<0||position>getListLength()){System.out.println("插入位置不合法");return;}if (position==0){headinsert(value);}else if (position==getListLength()){insert(value);}else {//创建新节点ListNode node = new ListNode(value);ListNode index = head;ListNode pre = null;//找相关位置int count=0;while (index!=null){if (count==position){node.next=index;pre.next=node;return;}pre=index;index=index.next;count++;}}}
7.任意位置删除
//任意位置删除public void deleteNodeAtIndex(int position){//判断插入位置是否合法if(position<0||position>getListLength()-1){System.out.println("删除位置不合法");return;}//删除位置是0号位置if (position==0){head=head.next;return;}//删除位置不是0号位置ListNode index = head;ListNode pre = null;//找相关位置int count=0;while (index!=null){if (count==position){pre.next=index.next;return;}pre=index;index=index.next;count++;}}
8.找中间节点,只遍历一次
//找到中间节点,只遍历一遍public ListNode findMiddle(){ListNode fast = head;ListNode show = head;while (fast!=null&&fast.next!=null){fast=fast.next.next;show=show.next;}return show;}
9.判断链表是否成环
//判断链表是否成环public boolean hasCycle(){ListNode fast = head;ListNode show = head;while (fast!=null&&fast.next!=null){fast=fast.next.next;show=show.next;if (fast==show){return true;}}return false;}
10.判断成环链表的起始节点
//判断成环链表的起始节点public ListNode findHasCycle(){ListNode fast = head;ListNode show = head;while (fast!=null&&fast.next!=null){fast=fast.next.next;show=show.next;if (fast==show){show=head;while (show!=fast){fast= fast.next;show= show.next;}return show;}}return null;}
11.截取单链表后k个节点
//截取单链表后k个节点public ListNode endNode(int k){ListNode fast = head;ListNode show = head;//fast先走k步for (int i = 0; i < k; i++) {fast=fast.next;}while (fast!=null){show= show.next;fast= fast.next;}return show;}
12.翻转链表,在链表上直接翻转
//翻转链表,在链表上直接翻转public ListNode fanzhuan(){ListNode index = null;ListNode pre = null;while (head!=null){index=head.next;head.next=pre;pre=head;head=index;}head=pre;return head;}