0727

topcode/eastplain/eastplain.iml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="jdk" jdkName="1.8" jdkType="JavaSDK" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

topcode/eastplain/src/infrastructure/Node.java

@@ -0,0 +1,26 @@
+package infrastructure;
+
+import java.util.List;
+
+/**
+ * 定义 N叉树的结构
+ *
+ * @author EastPlain
+ * @date 2021/7/27 22:38
+ */
+public class Node {
+
+    public int val;
+    public List<Node> children;
+
+    public Node() {}
+
+    public Node(int _val) {
+        val = _val;
+    }
+
+    public Node(int _val, List<Node> _children) {
+        val = _val;
+        children = _children;
+    }
+}

topcode/eastplain/src/infrastructure/TreeNode.java

@@ -0,0 +1,20 @@
+package infrastructure;
+
+/**
+ * 定义 二叉树的结构
+ *
+ * @author EastPlain
+ * @date 2021/7/26 21:52
+ */
+public class TreeNode {
+
+    public int val;
+    public TreeNode left;
+    public TreeNode right;
+
+    public TreeNode(int val, TreeNode left, TreeNode right) {
+        this.val = val;
+        this.left = left;
+        this.right = right;
+    }
+}

topcode/eastplain/src/method/BinaryTreeInorder.java

@@ -0,0 +1,60 @@
+package method;
+
+import infrastructure.TreeNode;
+
+import javax.print.DocFlavor;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Stack;
+
+/**
+ * 二叉树的中序遍历
+ * # lc0094
+ *
+ * @author EastPlain
+ * @date 2021/7/26 23:18
+ */
+public class BinaryTreeInorder {
+
+    /**
+     * 递归法
+     */
+    public List<Integer> recur(TreeNode root) {
+
+        return null;
+    }
+
+    /**
+     * 迭代法
+     */
+    public List<Integer> iteration(TreeNode root) {
+
+        Stack<TreeNode> stack = new Stack<>();
+        List<Integer> ans = new ArrayList<>();
+
+        if (root == null) {
+            return ans;
+        }
+
+        TreeNode current = root;
+
+        while (! stack.isEmpty() || current != null) {
+
+            while (current != null) {
+                stack.push(current);
+                current = current.left;
+            }
+
+           TreeNode node = stack.pop();
+            ans.add(node.val);
+
+            if (node.right != null) {
+                stack.push(node.right);
+            }
+        }
+
+        return ans;
+    }
+}
+
+

topcode/eastplain/src/method/BinaryTreeLayer.java

@@ -0,0 +1,53 @@
+package method;
+
+import infrastructure.TreeNode;
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Queue;
+
+/**
+ * 二叉树的层序遍历
+ * # lc0102
+ *
+ * @author EastPlain
+ * @date 2021/7/26 23:37
+ */
+public class BinaryTreeLayer {
+
+    public List<List<Integer>> method(TreeNode root) {
+
+        List<List<Integer>> ans = new ArrayList<>();
+        Queue<TreeNode> queue = new LinkedList<>();
+
+        if (root == null) {
+            return ans;
+        }
+
+        queue.add(root);
+
+        while (! queue.isEmpty()) {
+
+            int size = queue.size();
+            List<Integer> temp = new ArrayList<>();
+
+            for (int i = 0; i < size; i++) {
+                TreeNode current = queue.remove();
+                temp.add(current.val);
+
+                if (current.left != null) {
+                    queue.add(current.left);
+                }
+
+                if (current.right != null) {
+                    queue.add(current.right);
+                }
+            }
+
+            ans.add(temp);
+        }
+
+        return ans;
+    }
+}