diff --git a/java/0144-binary-tree-preorder-traversal.java b/java/0144-binary-tree-preorder-traversal.java new file mode 100644 index 000000000..8662967b3 --- /dev/null +++ b/java/0144-binary-tree-preorder-traversal.java @@ -0,0 +1,39 @@ +/** + * Definition for a binary tree node. + * public class TreeNode { + * int val; + * TreeNode left; + * TreeNode right; + * TreeNode() {} + * TreeNode(int val) { this.val = val; } + * TreeNode(int val, TreeNode left, TreeNode right) { + * this.val = val; + * this.left = left; + * this.right = right; + * } + * } + */ +class Solution { + + static void preOrder(TreeNode root, List res){ + + + if(root == null){ + return; + } + res.add(root.val); + preOrder(root.left,res); + preOrder(root.right,res); + + } + + public List preorderTraversal(TreeNode root) { + + List res = new ArrayList<>(); + + preOrder(root,res); + + return res; + + } +} \ No newline at end of file