solve

Author: sonjh1217

same-tree/sonjh1217.swift

@@ -0,0 +1,30 @@
+/**
+ * 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
+ *     }
+ * }
+ */
+class Solution {
+    // O(n) time, O(h) space h = 트리의 높이. 최악: n, 평균: log n
+    func isSameTree(_ p: TreeNode?, _ q: TreeNode?) -> Bool {
+        switch (p, q) {
+        case (nil, nil):
+            return true
+        case (let p, let q)
+            return p.val == q.val
+            && isSameTree(p.left, q.left)
+            && isSameTree(p.right, q.right)
+        default:
+            return false
+        }
+    }
+}