From f875a1841e2c5e051b45ce264694f047ac4d713f Mon Sep 17 00:00:00 2001
From: dingjiawen <745518019@qq.com>
Date: Mon, 5 Sep 2022 15:19:07 +0800
Subject: [PATCH] =?UTF-8?q?leecode=E6=9B=B4=E6=96=B0?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../leecode/listnode/MyLinkedList.java        | 301 +++++++++++++++++
 .../leecode/listnode/MyLinkedList1.java       | 313 ++++++++++++++++++
 .../leecode/listnode/RemoveElement.java       | 157 +++++++++
 3 files changed, 771 insertions(+)
 create mode 100644 Leecode/src/main/java/com/markilue/leecode/listnode/MyLinkedList.java
 create mode 100644 Leecode/src/main/java/com/markilue/leecode/listnode/MyLinkedList1.java
 create mode 100644 Leecode/src/main/java/com/markilue/leecode/listnode/RemoveElement.java

diff --git a/Leecode/src/main/java/com/markilue/leecode/listnode/MyLinkedList.java b/Leecode/src/main/java/com/markilue/leecode/listnode/MyLinkedList.java
new file mode 100644
index 0000000..257ae3c
--- /dev/null
+++ b/Leecode/src/main/java/com/markilue/leecode/listnode/MyLinkedList.java
@@ -0,0 +1,301 @@
+package com.markilue.leecode.listnode;
+
+import org.junit.Test;
+
+/**
+ * 设计链表：
+ * 设计链表的实现。您可以选择使用单链表或双链表。单链表中的节点应该具有两个属性：val和next。val是当前节点的值，next是指向下一个节点的指针/引用。如果要使用双向链表，则还需要一个属性prev以指示链表中的上一个节点。假设链表中的所有节点都是 0-index 的。
+ *
+ * 在链表类中实现这些功能：
+ *
+ * get(index)：获取链表中第index个节点的值。如果索引无效，则返回-1。
+ * addAtHead(val)：在链表的第一个元素之前添加一个值为val的节点。插入后，新节点将成为链表的第一个节点。
+ * addAtTail(val)：将值为val 的节点追加到链表的最后一个元素。
+ * addAtIndex(index,val)：在链表中的第index个节点之前添加值为val 的节点。如果index等于链表的长度，则该节点将附加到链表的末尾。如果 index 大于链表长度，则不会插入节点。如果index小于0，则在头部插入节点。
+ * deleteAtIndex(index)：如果索引index 有效，则删除链表中的第index 个节点。
+ *
+ * Your MyLinkedList object will be instantiated and called as such:
+ * MyLinkedList obj = new MyLinkedList();
+ * int param_1 = obj.get(index);
+ * obj.addAtHead(val);
+ * obj.addAtTail(val);
+ * obj.addAtIndex(index,val);
+ * obj.deleteAtIndex(index);
+ */
+public class MyLinkedList {
+
+    public ListNode head;
+
+    public MyLinkedList() {
+
+    }
+
+    public int get(int index) {
+
+        int count = 0;
+        //避免head发生变化
+        ListNode temp=head;
+        while (count!=index&&temp!=null){
+            temp = temp.next;
+            count++;
+        }
+        //找到了对应的index
+        if(count==index){
+            if(temp!=null){
+                return temp.val;
+            }
+        }
+
+        return -1;
+
+    }
+
+    public void addAtHead(int val) {
+        if(head==null){
+            head=new ListNode(val);
+            return;
+        }
+        ListNode neededAddNode = new ListNode(val);
+        ListNode tempHead=new ListNode(0);
+        tempHead.next=neededAddNode;
+        neededAddNode.next=head;
+        head=tempHead.next;
+
+    }
+
+    public void addAtTail(int val) {
+        if(head==null){
+            head=new ListNode(val);
+            return;
+        }
+        ListNode temp=head;
+        while (temp.next!=null){
+            temp=temp.next;
+        }
+        temp.next=new ListNode(val);
+
+    }
+
+    public void addAtIndex(int index, int val) {
+        if(index>getSize()){
+            return;
+        }
+
+        if(index<=0){
+            addAtHead(val);
+        }
+
+        int count = 0;
+        //避免head发生变化
+        ListNode temp=head;
+        while (count!=index-1&&temp.next!=null){
+            temp = temp.next;
+            count++;
+        }
+        //找到了对应的index
+        if(count==index-1){
+            ListNode need = new ListNode(val);
+            need.next=temp.next;
+            temp.next=need;
+        }else {
+            System.out.println("index超过限制");
+        }
+
+    }
+
+    public void deleteAtIndex(int index) {
+
+        if(head==null){
+            return;
+        }
+
+        if(index==0){
+            head=head.next;
+            return;
+        }
+
+        int count = 0;
+        //避免head发生变化
+        ListNode temp=head;
+        while (count!=index-1&&temp.next!=null){
+            temp = temp.next;
+            count++;
+        }
+        //找到了对应的index
+        if(count==index-1){
+            if(temp.next!=null){
+                temp.next=temp.next.next;
+            }
+        }else {
+            System.out.println("index超过限制");
+        }
+
+    }
+
+    public void printList(ListNode head) {
+
+        if(head==null){
+            System.out.println("链表为空");
+            return;
+        }
+
+        while (head!=null){
+            System.out.printf(head.val+"->");
+            head=head.next;
+        }
+
+        System.out.println();
+
+
+    }
+
+    public int getSize(){
+        int size=0;
+        ListNode temp=head;
+        while (temp!=null){
+            size+=1;
+            temp=temp.next;
+        }
+
+        return size;
+    }
+
+
+    @Test
+    public void test(){
+        MyLinkedList linkedList = new MyLinkedList();
+        linkedList.addAtHead(1);
+        printList(linkedList.head);
+        System.out.println();
+        linkedList.addAtTail(3);
+        printList(linkedList.head);
+        System.out.println();
+        linkedList.addAtIndex(1,2);   //链表变为1-> 2-> 3
+        printList(linkedList.head);
+        System.out.println();
+        System.out.println(linkedList.get(1));
+//        printList(linkedList.head);
+        System.out.println();
+        linkedList.deleteAtIndex(1);  //现在链表是1-> 3
+        printList(linkedList.head);
+        System.out.println();
+        System.out.println(linkedList.get(1));
+
+
+    }
+    @Test
+    public void test1(){
+        MyLinkedList linkedList = new MyLinkedList();
+        linkedList.addAtHead(7);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(2);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(1);
+        printList(linkedList.head);
+
+        linkedList.addAtIndex(3,0);
+        printList(linkedList.head);
+
+        linkedList.deleteAtIndex(2);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(6);
+        printList(linkedList.head);
+
+        linkedList.addAtTail(4);
+        printList(linkedList.head);
+
+        System.out.println(linkedList.get(4));
+
+        linkedList.addAtHead(4);
+        printList(linkedList.head);
+
+        linkedList.addAtIndex(5,0);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(6);
+        printList(linkedList.head);
+
+
+//        System.out.println(linkedList.get(1));
+////        printList(linkedList.head);
+//        System.out.println();
+//        linkedList.deleteAtIndex(1);  //现在链表是1-> 3
+//        printList(linkedList.head);
+//        System.out.println();
+//        System.out.println(linkedList.get(1));
+
+
+    }
+    @Test
+    public void test2(){
+        MyLinkedList linkedList = new MyLinkedList();
+        linkedList.addAtHead(2);
+        printList(linkedList.head);
+
+        linkedList.deleteAtIndex(1);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(2);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(7);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(3);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(2);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(5);
+        printList(linkedList.head);
+
+        linkedList.addAtTail(5);
+        printList(linkedList.head);
+
+        System.out.println(linkedList.get(5));
+
+        linkedList.deleteAtIndex(6);
+        printList(linkedList.head);
+
+        linkedList.deleteAtIndex(4);
+        printList(linkedList.head);
+
+
+    }
+
+    @Test
+    public void test3(){
+        MyLinkedList linkedList = new MyLinkedList();
+        linkedList.addAtHead(1);
+        printList(linkedList.head);
+
+
+        linkedList.addAtTail(3);
+        printList(linkedList.head);
+
+        linkedList.addAtIndex(1,2);
+        printList(linkedList.head);
+
+
+        System.out.println(linkedList.get(1));
+
+        linkedList.deleteAtIndex(1);
+        printList(linkedList.head);
+
+        System.out.println(linkedList.get(1));
+
+
+    }
+
+    /*
+        错了四五次之后通过
+        内存超过79.95%，速度超过9.96%，慢的原因:每次都要算一遍getSize
+        改进:维护一个变量size,每次容量变化都让size也跟着变化一次;此外，还可以维护一个虚拟的头结点，不存放任何数据；
+        具体操作参考MyLinkedList1
+     */
+}
+
diff --git a/Leecode/src/main/java/com/markilue/leecode/listnode/MyLinkedList1.java b/Leecode/src/main/java/com/markilue/leecode/listnode/MyLinkedList1.java
new file mode 100644
index 0000000..e022842
--- /dev/null
+++ b/Leecode/src/main/java/com/markilue/leecode/listnode/MyLinkedList1.java
@@ -0,0 +1,313 @@
+package com.markilue.leecode.listnode;
+
+import org.junit.Test;
+
+/**
+ * 设计链表：
+ * 设计链表的实现。您可以选择使用单链表或双链表。单链表中的节点应该具有两个属性：val和next。val是当前节点的值，next是指向下一个节点的指针/引用。如果要使用双向链表，则还需要一个属性prev以指示链表中的上一个节点。假设链表中的所有节点都是 0-index 的。
+ * <p>
+ * 在链表类中实现这些功能：
+ * <p>
+ * get(index)：获取链表中第index个节点的值。如果索引无效，则返回-1。
+ * addAtHead(val)：在链表的第一个元素之前添加一个值为val的节点。插入后，新节点将成为链表的第一个节点。
+ * addAtTail(val)：将值为val 的节点追加到链表的最后一个元素。
+ * addAtIndex(index,val)：在链表中的第index个节点之前添加值为val 的节点。如果index等于链表的长度，则该节点将附加到链表的末尾。如果 index 大于链表长度，则不会插入节点。如果index小于0，则在头部插入节点。
+ * deleteAtIndex(index)：如果索引index 有效，则删除链表中的第index 个节点。
+ * <p>
+ * Your MyLinkedList object will be instantiated and called as such:
+ * MyLinkedList obj = new MyLinkedList();
+ * int param_1 = obj.get(index);
+ * obj.addAtHead(val);
+ * obj.addAtTail(val);
+ * obj.addAtIndex(index,val);
+ * obj.deleteAtIndex(index);
+ */
+public class MyLinkedList1 {
+
+    //该head为虚拟节点,不存放任何数据
+    public ListNode head;
+    public int size;
+
+    public MyLinkedList1() {
+        head = new ListNode(0);
+        size = 0;
+    }
+
+    public int get(int index) {
+
+        if (size < index+1 || index < 0) {
+            return -1;
+        }
+
+        //避免head发生变化
+        ListNode temp = head.next;
+        while (index-- > 0) {
+            temp = temp.next;
+        }
+        return temp.val;
+
+    }
+
+    public void addAtHead(int val) {
+
+        ListNode need = new ListNode(val);
+        need.next = head.next;
+        head.next = need;
+        size++;
+    }
+
+    public void addAtTail(int val) {
+
+        ListNode need = new ListNode(val);
+        ListNode temp = head;
+
+        while (temp.next != null) {
+            temp = temp.next;
+        }
+
+        temp.next = need;
+        size++;
+    }
+
+    public void addAtIndex(int index, int val) {
+
+        if (index > size || index < 0) {
+            return;
+        }
+        ListNode temp = head;
+        while (index-- > 0) {
+            temp = temp.next;
+        }
+
+        ListNode need = new ListNode(val);
+        need.next = temp.next;
+        temp.next = need;
+        size++;
+    }
+
+    public void deleteAtIndex(int index) {
+
+        if (index > size-1 || index < 0) {
+            return;
+        }
+        ListNode temp = head;
+        while (index-- > 0) {
+            temp = temp.next;
+        }
+
+        temp.next = temp.next.next;
+        size--;
+    }
+
+    public void printList(ListNode head) {
+
+       ListNode temp=head.next;
+
+       while (temp!=null){
+           System.out.printf(temp.val+"->");
+           temp=temp.next;
+       }
+
+        System.out.println();
+
+
+    }
+
+    public int getSize() {
+
+        return size;
+
+    }
+
+
+    @Test
+    public void test() {
+        MyLinkedList1 linkedList = new MyLinkedList1();
+        linkedList.addAtHead(1);
+        printList(linkedList.head);
+        System.out.println();
+        linkedList.addAtTail(3);
+        printList(linkedList.head);
+        System.out.println();
+        linkedList.addAtIndex(1, 2);   //链表变为1-> 2-> 3
+        printList(linkedList.head);
+        System.out.println();
+        System.out.println(linkedList.get(1));
+//        printList(linkedList.head);
+        System.out.println();
+        linkedList.deleteAtIndex(1);  //现在链表是1-> 3
+        printList(linkedList.head);
+        System.out.println();
+        System.out.println(linkedList.get(1));
+
+
+    }
+
+    @Test
+    public void test1() {
+        MyLinkedList1 linkedList = new MyLinkedList1();
+        linkedList.addAtHead(7);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(2);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(1);
+        printList(linkedList.head);
+
+        linkedList.addAtIndex(3, 0);
+        printList(linkedList.head);
+
+        linkedList.deleteAtIndex(2);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(6);
+        printList(linkedList.head);
+
+        linkedList.addAtTail(4);
+        printList(linkedList.head);
+
+        System.out.println(linkedList.get(4));
+
+        linkedList.addAtHead(4);
+        printList(linkedList.head);
+
+        linkedList.addAtIndex(5, 0);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(6);
+        printList(linkedList.head);
+
+
+//        System.out.println(linkedList.get(1));
+////        printList(linkedList.head);
+//        System.out.println();
+//        linkedList.deleteAtIndex(1);  //现在链表是1-> 3
+//        printList(linkedList.head);
+//        System.out.println();
+//        System.out.println(linkedList.get(1));
+
+
+    }
+
+    @Test
+    public void test2() {
+        MyLinkedList1 linkedList = new MyLinkedList1();
+        linkedList.addAtHead(2);
+        printList(linkedList.head);
+
+        linkedList.deleteAtIndex(1);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(2);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(7);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(3);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(2);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(5);
+        printList(linkedList.head);
+
+        linkedList.addAtTail(5);
+        printList(linkedList.head);
+
+        System.out.println(linkedList.get(5));
+
+        linkedList.deleteAtIndex(6);
+        printList(linkedList.head);
+
+        linkedList.deleteAtIndex(4);
+        printList(linkedList.head);
+
+
+    }
+
+    @Test
+    public void test3() {
+        MyLinkedList1 linkedList = new MyLinkedList1();
+        linkedList.addAtHead(1);
+        printList(linkedList.head);
+
+
+        linkedList.addAtTail(3);
+        printList(linkedList.head);
+
+        linkedList.addAtIndex(1, 2);
+        printList(linkedList.head);
+
+
+        System.out.println(linkedList.get(1));
+
+        linkedList.deleteAtIndex(1);
+        printList(linkedList.head);
+
+        System.out.println(linkedList.get(1));
+
+
+    }
+
+    @Test
+    public void test4() {
+        MyLinkedList1 linkedList = new MyLinkedList1();
+        linkedList.addAtHead(4);
+        printList(linkedList.head);
+
+        System.out.println(linkedList.get(1));
+
+        linkedList.addAtHead(1);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(5);
+        printList(linkedList.head);
+
+        linkedList.deleteAtIndex(3);
+        printList(linkedList.head);
+
+        linkedList.addAtHead(7);
+        printList(linkedList.head);
+
+        System.out.println(linkedList.get(3));
+
+        System.out.println(linkedList.get(3));
+
+        System.out.println(linkedList.get(3));
+
+        linkedList.addAtHead(1);
+        printList(linkedList.head);
+
+
+        linkedList.deleteAtIndex(4);
+        printList(linkedList.head);
+
+
+
+
+    }
+
+    /*
+        内存超过99.29%，速度超过30.86%
+     */
+}
+
+class ListNode {
+    public int val;
+    public ListNode next;
+
+    public ListNode() {
+    }
+
+    public ListNode(int val) {
+        this.val = val;
+    }
+
+    public ListNode(int val, ListNode next) {
+        this.val = val;
+        this.next = next;
+    }
+}
diff --git a/Leecode/src/main/java/com/markilue/leecode/listnode/RemoveElement.java b/Leecode/src/main/java/com/markilue/leecode/listnode/RemoveElement.java
new file mode 100644
index 0000000..0f95961
--- /dev/null
+++ b/Leecode/src/main/java/com/markilue/leecode/listnode/RemoveElement.java
@@ -0,0 +1,157 @@
+package com.markilue.leecode.listnode;
+
+import org.junit.Test;
+
+/**
+ * 移除链表元素:
+ * 给你一个链表的头节点 head 和一个整数 val ，请你删除链表中所有满足 Node.val == val 的节点，并返回 新的头节点 。
+ */
+public class RemoveElement {
+
+
+    @Test
+    public void test1() {
+        ListNode listNode = new ListNode(1);
+        ListNode listNode2 = new ListNode(2);
+        ListNode listNode3 = new ListNode(6);
+        ListNode listNode4 = new ListNode(3);
+        ListNode listNode5 = new ListNode(4);
+        ListNode listNode6 = new ListNode(5);
+        ListNode listNode7 = new ListNode(6);
+        listNode.next = listNode2;
+        listNode2.next = listNode3;
+        listNode3.next = listNode4;
+        listNode4.next = listNode5;
+        listNode5.next = listNode6;
+        listNode6.next = listNode7;
+        ListNode result = removeElements(listNode, 6);
+        print(result);
+
+    }
+
+    @Test
+    public void test2() {
+
+        ListNode listNode = removeElements(null, 1);
+        print(listNode);
+
+    }
+
+    @Test
+    public void test3() {
+
+        ListNode listNode = new ListNode(7);
+        ListNode listNode2 = new ListNode(7);
+        ListNode listNode3 = new ListNode(7);
+        ListNode listNode4 = new ListNode(7);
+        listNode.next = listNode2;
+        listNode2.next = listNode3;
+        listNode3.next = listNode4;
+
+        ListNode result = removeElements1(listNode, 7);
+        print(result);
+
+    }
+
+
+    /**
+     * 内存击败45%，速度击败50%
+     * @param head
+     * @param val
+     * @return
+     */
+    public ListNode removeElements(ListNode head, int val) {
+
+        if (head == null) {
+            return head;
+        }
+
+        //创建一个虚拟头节点用于返回
+        ListNode listNode = new ListNode();
+        listNode.next = head;
+        ListNode recu = listNode;
+
+
+        while (recu.next != null) {
+            print(listNode);
+            System.out.println();
+
+            if (recu.next.val == val) {
+                recu.next = recu.next.next;
+            } else {
+                recu = recu.next;
+            }
+        }
+
+        return listNode.next;
+
+    }
+
+    /**
+     * 改进版，不一定要直接找下一个，可以找下一个不是val的元素
+     * 速度还是击败50%，内存击败84%
+     * @param head
+     * @param val
+     * @return
+     */
+    public ListNode removeElements1(ListNode head, int val) {
+
+        if (head == null) {
+            return head;
+        }
+
+        //创建一个虚拟头节点用于返回
+        ListNode listNode = new ListNode();
+        listNode.next = head;
+        ListNode recu = listNode;
+
+
+        while (recu.next != null) {
+            print(listNode);
+            System.out.println();
+
+            if (recu.next.val == val) {
+                while (recu.next.next!=null&&recu.next.next.val==val){
+                    recu.next.next=recu.next.next.next;
+                }
+                recu.next = recu.next.next;
+            } else {
+                recu = recu.next;
+            }
+        }
+
+        return listNode.next;
+
+    }
+
+
+    public class ListNode {
+        public int val;
+        public ListNode next;
+
+        public ListNode() {
+        }
+
+        public ListNode(int val) {
+            this.val = val;
+        }
+
+        public ListNode(int val, ListNode next) {
+            this.val = val;
+            this.next = next;
+        }
+    }
+
+    public void print(ListNode listNode) {
+        if (listNode == null) {
+            System.out.println("链表为空");
+            return;
+        }
+        while (listNode != null) {
+            System.out.printf(listNode.val + "->");
+            listNode = listNode.next;
+        }
+    }
+
+
+}