From 007813f33b731210fb75f65c6a1309dd47f7b9a1 Mon Sep 17 00:00:00 2001
From: liulei <718356979@qq.com>
Date: Thu, 24 Jun 2021 08:40:16 +0800
Subject: [PATCH] =?UTF-8?q?=E6=9B=B4=E6=96=B0=E4=BA=8C=E5=8F=89=E6=A0=91?=
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---
 problems/二叉树的迭代遍历.md | 75 +++++++++++++++++++++++++++-
 1 file changed, 74 insertions(+), 1 deletion(-)

diff --git a/problems/二叉树的迭代遍历.md b/problems/二叉树的迭代遍历.md
index 8706dc47..30b921ff 100644
--- a/problems/二叉树的迭代遍历.md
+++ b/problems/二叉树的迭代遍历.md
@@ -155,9 +155,82 @@ public:
 
 ## 其他语言版本
 
-
 Java：
 
+```java
+// 前序遍历顺序：中-左-右，入栈顺序：中-右-左
+class Solution {
+    public List<Integer> preorderTraversal(TreeNode root) {
+        List<Integer> result = new ArrayList<>();
+        if (root == null){
+            return result;
+        }
+        Stack<TreeNode> stack = new Stack<>();
+        stack.push(root);
+        while (!stack.isEmpty()){
+            TreeNode node = stack.pop();
+            result.add(node.val);
+            if (node.right != null){
+                stack.push(node.right);
+            }
+            if (node.left != null){
+                stack.push(node.left);
+            }
+        }
+        return result;
+    }
+}
+
+// 中序遍历顺序: 左-中-右 入栈顺序： 左-右
+class Solution {
+    public List<Integer> inorderTraversal(TreeNode root) {
+        List<Integer> result = new ArrayList<>();
+        if (root == null){
+            return result;
+        }
+        Stack<TreeNode> stack = new Stack<>();
+        TreeNode cur = root;
+        while (cur != null || !stack.isEmpty()){
+           if (cur != null){
+               stack.push(cur);
+               cur = cur.left;
+           }else{
+               cur = stack.pop();
+               result.add(cur.val);
+               cur = cur.right;
+           }
+        }
+        return result;
+    }
+}
+
+// 后序遍历顺序 左-右-中 入栈顺序：中-左-右 出栈顺序：中-右-左， 最后翻转结果
+class Solution {
+    public List<Integer> postorderTraversal(TreeNode root) {
+        List<Integer> result = new ArrayList<>();
+        if (root == null){
+            return result;
+        }
+        Stack<TreeNode> stack = new Stack<>();
+        stack.push(root);
+        while (!stack.isEmpty()){
+            TreeNode node = stack.pop();
+            result.add(node.val);
+            if (node.left != null){
+                stack.push(node.left);
+            }
+            if (node.right != null){
+                stack.push(node.right);
+            }
+        }
+        Collections.reverse(result);
+        return result;
+    }
+}
+```
+
+
+
 
 Python：
 ```python3