@@ -155,9 +155,82 @@ public:
155155
156156## 其他语言版本
157157
158-
159158Java：
160159
160+ ```java
161+ // 前序遍历顺序：中-左-右，入栈顺序：中-右-左
162+ class Solution {
163+ public List<Integer> preorderTraversal(TreeNode root) {
164+ List<Integer> result = new ArrayList<>();
165+ if (root == null){
166+ return result;
167+ }
168+ Stack<TreeNode> stack = new Stack<>();
169+ stack.push(root);
170+ while (!stack.isEmpty()){
171+ TreeNode node = stack.pop();
172+ result.add(node.val);
173+ if (node.right != null){
174+ stack.push(node.right);
175+ }
176+ if (node.left != null){
177+ stack.push(node.left);
178+ }
179+ }
180+ return result;
181+ }
182+ }
183+
184+ // 中序遍历顺序: 左-中-右 入栈顺序： 左-右
185+ class Solution {
186+ public List<Integer> inorderTraversal(TreeNode root) {
187+ List<Integer> result = new ArrayList<>();
188+ if (root == null){
189+ return result;
190+ }
191+ Stack<TreeNode> stack = new Stack<>();
192+ TreeNode cur = root;
193+ while (cur != null || !stack.isEmpty()){
194+ if (cur != null){
195+ stack.push(cur);
196+ cur = cur.left;
197+ }else{
198+ cur = stack.pop();
199+ result.add(cur.val);
200+ cur = cur.right;
201+ }
202+ }
203+ return result;
204+ }
205+ }
206+
207+ // 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
208+ class Solution {
209+ public List<Integer> postorderTraversal(TreeNode root) {
210+ List<Integer> result = new ArrayList<>();
211+ if (root == null){
212+ return result;
213+ }
214+ Stack<TreeNode> stack = new Stack<>();
215+ stack.push(root);
216+ while (!stack.isEmpty()){
217+ TreeNode node = stack.pop();
218+ result.add(node.val);
219+ if (node.left != null){
220+ stack.push(node.left);
221+ }
222+ if (node.right != null){
223+ stack.push(node.right);
224+ }
225+ }
226+ Collections.reverse(result);
227+ return result;
228+ }
229+ }
230+ ```
231+
232+
233+
161234
162235Python：
163236``` python3