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‎progress.txt

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easy :
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列表操作 21 83
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medium:
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hard:
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可以分为基础的数据结构，比如数组、链表、栈、队列、二叉树、堆的使用，这几种常见的数据结构的基础操作一定要很熟悉，
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比如链表逆置、删除、获取第 K 个元素、判断是否有环等，二叉树翻转、深度遍历、层级遍历、求树深度、公共父节点等。

‎src/com/blankj/easy/_0021/Solution.java

Lines changed: 30 additions & 1 deletion
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package com.blankj.easy._021;
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import com.blankj.structure.ListNode;
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import com.blankj.structure.ListNodeMe;
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import static java.lang.System.out;
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/**
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* <pre>
@@ -28,12 +31,38 @@ public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
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return head.next;
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}
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public static void main(String[] args) {
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public static void main2(String[] args) {
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Solution solution = new Solution();
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ListNode listNode0 = ListNode.createTestData("[1,3,5,7,9]");
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ListNode listNode1 = ListNode.createTestData("[2,4,6,8,10]");
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ListNode.print(listNode0);
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ListNode.print(listNode1);
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ListNode.print(solution.mergeTwoLists(listNode0, listNode1));
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}
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public static void main(String[] args) {
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Solution solution = new Solution();
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ListNodeMe listNode0 = ListNodeMe.createTestData("[1,3,5,7,9]");
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ListNodeMe listNode1 = ListNodeMe.createTestData("[1,2,4,6,8,10]");
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ListNodeMe.print(listNode0);
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ListNodeMe.print(listNode1);
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ListNodeMe.print(solution.mergeTwoLists(listNode0, listNode1));
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}
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private ListNodeMe mergeTwoLists(ListNodeMe listNode0, ListNodeMe listNode1) {
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ListNodeMe header = new ListNodeMe(-1);
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ListNodeMe temp = header;
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while (listNode0 != null && listNode1 != null) {
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if (listNode0.data < listNode1.data) {
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temp.next = listNode0;
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listNode0 = listNode0.next;
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} else {
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temp.next = listNode1;
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listNode1 = listNode1.next;
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}
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temp = temp.next;
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}
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temp.next = listNode0 == null ? listNode1 : listNode0;
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return header.next;
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}
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}

‎src/com/blankj/easy/_0083/Solution.java

Lines changed: 119 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,14 @@
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package com.blankj.easy._083;
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import com.blankj.structure.ListNode;
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import com.blankj.structure.ListNodeMe;
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import java.util.Collections;
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import java.util.HashMap;
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import java.util.Map;
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import static java.lang.System.in;
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import static java.lang.System.out;
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/**
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* <pre>
@@ -24,9 +32,119 @@ public ListNode deleteDuplicates(ListNode head) {
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return head;
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}
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27-
public static void main(String[] args) {
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public static void main2(String[] args) {
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Solution solution = new Solution();
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ListNode.print(solution.deleteDuplicates(ListNode.createTestData("[1,1,2]")));
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ListNode.print(solution.deleteDuplicates(ListNode.createTestData("[1,1,2,3,3]")));
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}
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public static void main_me(String[] args) {
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Solution solution = new Solution();
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// 升序的链表排重很好做了
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ListNodeMe listNode1 = ListNodeMe.createTestData("[1,2,2,4,4,6,8,10]");
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ListNodeMe.print(listNode1);
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solution.deleteDuplicates2(listNode1);
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}
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public static void main3(String[] args) {
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Solution solution = new Solution();
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// ListNodeMe listNode1 = ListNodeMe.createTestData("[1,2,2,4,4,6,8,10]");
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ListNodeMe listNode1 = ListNodeMe.createCirlceList("[1,2,2,4,4,6,8,10]");
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boolean looperList = solution.isLooperList(listNode1);
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out.println("is cirlce list ? " + looperList);
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}
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public static void main(String[] args) {
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Solution solution = new Solution();
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ListNodeMe listNode1 = ListNodeMe.createTestData("[1,2,3,4,5,6,8,10]");
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// ListNodeMe.print(solution.reverseList2(listNode1));
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listNode1 = solution.deleteByIndex(listNode1, 3);
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ListNodeMe.print(listNode1);
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}
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private void deleteDuplicates2(ListNodeMe listNode1) {
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ListNodeMe temp = listNode1;
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while (temp != null && temp.next != null) {
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if (temp.data == temp.next.data) {
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temp.next = temp.next.next;
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} else {
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temp = temp.next;
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}
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}
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ListNodeMe.print(listNode1);
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}
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/**
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* 判断是否有环
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* @param temp
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* @return
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*/
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private boolean isLooperList(ListNodeMe temp) {
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Object o = new Object();
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Map<ListNodeMe, Object> map = new HashMap<>();
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while (temp != null) {
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Object put = map.put(temp, o);
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if (put != null) {
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return true;
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}
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temp = temp.next;
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}
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return false;
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}
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public static ListNodeMe reverseList2(ListNodeMe current) {
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ListNodeMe pre = null;
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ListNodeMe next = null;
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while (current != null) {
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// 第一步: 保存下一个节点,因为需要打断
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next = current.next;
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// 第二步:打断
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current.next = pre;
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//后面两步为了下一次循环做准备
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pre = current;
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current = next;
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}
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return pre;
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}
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/**
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* 删除第index个元素, 从0开始 "[1,2,3,4,5,6,8,10]" 2
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* @param current
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* @param index
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*/
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public ListNodeMe deleteByIndex(ListNodeMe current, int index) { // 2
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ListNodeMe orign = current;
119+
if (index == 0) {
120+
return orign.next;
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}
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ListNodeMe pre = null;
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while (index > 0) {
124+
pre = orign;
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orign = orign.next;
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index--;
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}
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pre.next = orign.next;
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orign.next = null;
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return current;
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}
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/**
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* 反转列表
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* @param current
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* @return
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*/
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public static ListNodeMe reverseList(ListNodeMe current) {
139+
ListNodeMe pre = null;
140+
ListNodeMe next = null;
141+
while (current != null) {
142+
next = current.next;
143+
current.next = pre;
144+
145+
pre = current;
146+
current = next;
147+
}
148+
return pre;
149+
}
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}

‎src/com/blankj/structure/ListNodeMe.java

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package com.blankj.structure;
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import static java.lang.System.out;
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public class ListNodeMe {
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public int data;
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public ListNodeMe next;
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public ListNodeMe(int data) {
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this.data = data;
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}
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/**
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* 创建测试数据
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*
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* @param data [XX,XX,XX]
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* @return {@link ListNode}
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*/
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public static ListNodeMe createTestData(String data) {
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if ("[]".equals(data)) {
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return null;
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}
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String substring = data.substring(1, data.length()-1);
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out.println(substring);
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String[] arr = substring.split(",");
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ListNodeMe[] nodeArr = new ListNodeMe[arr.length];
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nodeArr[0] = new ListNodeMe(Integer.parseInt(arr[0]));
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for (int i = 1; i < arr.length; i++) {
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nodeArr[i] = new ListNodeMe(Integer.parseInt(arr[i]));
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nodeArr[i-1].next = nodeArr[i];
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}
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return nodeArr[0];
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}
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/**
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* 创建带有环的链表
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* @param data
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* @return
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*/
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public static ListNodeMe createCirlceList(String data) {
41+
if ("[]".equals(data)) {
42+
return null;
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}
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String substring = data.substring(1, data.length()-1);
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out.println(substring);
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String[] arr = substring.split(",");
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ListNodeMe[] nodeArr = new ListNodeMe[arr.length];
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nodeArr[0] = new ListNodeMe(Integer.parseInt(arr[0]));
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for (int i = 1; i < arr.length; i++) {
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nodeArr[i] = new ListNodeMe(Integer.parseInt(arr[i]));
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nodeArr[i-1].next = nodeArr[i];
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}
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nodeArr[arr.length - 1].next = nodeArr[0];
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return nodeArr[0];
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}
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public static void print(ListNodeMe nodeMe) {
58+
while (nodeMe != null) {
59+
out.print(nodeMe.data + " ");
60+
nodeMe = nodeMe.next;
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}
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out.println();
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}
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public static void main(String[] args) {
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ListNodeMe nodeMe = ListNodeMe.createTestData("[1,3,5,7,9]");
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print(nodeMe);
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}
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}

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