572

Author: TedTran2019

ruby/572-Subtree-of-Another-Tree.rb

@@ -0,0 +1,24 @@
+def is_subtree(root, sub_root)
+  return true if root.nil? && sub_root.nil?
+  return true if sub_root.nil?
+  return false if root.nil?
+
+  if same_tree?(root, sub_root)
+    true
+  else
+    is_subtree(root.left, sub_root) ||
+      is_subtree(root.right, sub_root)
+  end
+end
+
+def same_tree?(p, q)
+  if p.nil? && q.nil?
+    true
+  elsif p && q
+    (p.val == q.val) &&
+      same_tree?(p.left, q.left) &&
+      same_tree?(p.right, q.right)
+  else
+    false
+  end
+end