From 009662f6350017914db18adcbf0cef8c1aa522d4 Mon Sep 17 00:00:00 2001
From: qiuxuewei <qiuxuewei@baidu.com>
Date: Fri, 26 Nov 2021 14:26:01 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=2020.=20=E6=9C=89=E6=95=88?=
 =?UTF-8?q?=E7=9A=84=E6=8B=AC=E5=8F=B7=20Swift=E7=89=88=E6=9C=AC?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 problems/0020.有效的括号.md | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/problems/0020.有效的括号.md b/problems/0020.有效的括号.md
index 57aa5a01..5f597a1a 100644
--- a/problems/0020.有效的括号.md
+++ b/problems/0020.有效的括号.md
@@ -283,6 +283,29 @@ var isValid = function(s) {
 };
 ```
 
+Swift
+```swift
+func isValid(_ s: String) -> Bool {
+    var stack = [String.Element]()
+    for ch in s {
+        if ch == "(" {
+            stack.append(")")
+        } else if ch == "{" {
+            stack.append("}")
+        } else if ch == "[" {
+            stack.append("]")
+        } else {
+            let top = stack.last
+            if ch == top {
+                stack.removeLast()
+            } else {
+                return false
+            }
+        }
+    }
+    return stack.isEmpty
+}
+```
 
 -----------------------
 <div align="center"><img src=https://code-thinking.cdn.bcebos.com/pics/01二维码一.jpg width=500> </img></div>