feat: Add solution for LeetCode problem 572

Author: WhiteHyun

subtree-of-another-tree/WhiteHyun.swift

@@ -0,0 +1,37 @@
+//  
+//  572. Subtree of Another Tree
+//  https://leetcode.com/problems/subtree-of-another-tree/description/
+//  Dale-Study
+//  
+//  Created by WhiteHyun on 2024/05/12.
+//  
+
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     public var val: Int
+ *     public var left: TreeNode?
+ *     public var right: TreeNode?
+ *     public init() { self.val = 0; self.left = nil; self.right = nil; }
+ *     public init(_ val: Int) { self.val = val; self.left = nil; self.right = nil; }
+ *     public init(_ val: Int, _ left: TreeNode?, _ right: TreeNode?) {
+ *         self.val = val
+ *         self.left = left
+ *         self.right = right
+ *     }
+ * }
+ */
+extension TreeNode: Equatable {
+  public static func == (lhs: TreeNode, rhs: TreeNode) -> Bool {
+    lhs.val == rhs.val && lhs.left == rhs.left && lhs.right == rhs.right
+  }
+}
+
+final class Solution {
+  func isSubtree(_ node: TreeNode?, _ subRoot: TreeNode?) -> Bool {
+    if node == subRoot { return true }
+    else if node?.left != nil, isSubtree(node?.left, subRoot) { return true }
+    else if node?.right != nil, isSubtree(node?.right, subRoot) { return true }
+    return false
+  }
+}