feature: leaf similar trees dfs recursive solution

trees/LeafSimilarTrees.py

@@ -0,0 +1,17 @@
+from typing import Optional
+
+from trees.TreeNode import TreeNode
+
+
+# O(n) time || O(h) space
+def leaf_similar(self, root1: Optional[TreeNode], root2: Optional[TreeNode]) -> bool:
+    def dfs(node: TreeNode):
+        if not node:
+            return []
+
+        if not node.left and not node.right:
+            return [node.val]
+
+        return dfs(node.left) + dfs(node.right)
+
+    return dfs(root1) == dfs(root2)

trees/test/test_leaf_similar.py

@@ -0,0 +1,64 @@
+import unittest
+
+from trees.LeafSimilarTrees import leaf_similar
+from trees.TreeNode import TreeNode
+
+
+class MyTestCase(unittest.TestCase):
+    def test_leaf_similar(self):
+        root1 = TreeNode(
+            val=3,
+            left=TreeNode(
+                val=5,
+                left=TreeNode(val=6),
+                right=TreeNode(
+                    val=2,
+                    left=TreeNode(val=7),
+                    right=TreeNode(val=4)
+                )
+            ),
+            right=TreeNode(
+                val=1,
+                left=TreeNode(val=9),
+                right=TreeNode(val=8)
+            )
+        )
+
+        root2 = TreeNode(
+            val=3,
+            left=TreeNode(
+                val=5,
+                left=TreeNode(val=6),
+                right=TreeNode(val=7)
+            ),
+            right=TreeNode(
+                val=1,
+                left=TreeNode(val=4),
+                right=TreeNode(
+                    val=2,
+                    left=TreeNode(val=9),
+                    right=TreeNode(val=8)
+                )
+            )
+        )
+
+        self.assertEqual(True, leaf_similar(self, root1, root2))
+
+    def test_leaf_similar_1(self):
+        root1 = TreeNode(
+            val=1,
+            left=TreeNode(val=2),
+            right=TreeNode(val=3)
+        )
+
+        root2 = TreeNode(
+            val=1,
+            left=TreeNode(val=3),
+            right=TreeNode(val=2)
+        )
+
+        self.assertEqual(False, leaf_similar(self, root1, root2))
+
+
+if __name__ == '__main__':
+    unittest.main()