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 +} +``` -----------------------