famous tree questions

surajkeshari · web-flow · commit b4f2f6508dcc · 2022-10-07T03:17:17.000+05:30
diff --git a/java/Tree/Binary_Tree Inorder Traversal.java b/java/Tree/Binary_Tree Inorder Traversal.java
@@ -0,0 +1,21 @@
+class Solution {
+    public List<Integer> inorderTraversal(TreeNode root) {
+        List<Integer> res = new ArrayList<>();
+        if (root == null) return res;
+        Deque<TreeNode> stack = new ArrayDeque<>();
+        pushLeft(root, stack);
+        while (!stack.isEmpty()) {
+            TreeNode cur = stack.pop();
+            res.add(cur.val);
+            pushLeft(cur.right, stack);
+        }
+        return res;
+    }
+    
+    private void pushLeft(TreeNode root, Deque<TreeNode> stack) {
+        while (root != null) {
+            stack.push(root);
+            root = root.left;
+        }
+    }
+}
