diff --git a/problems/0020.有效的括号.md b/problems/0020.有效的括号.md index 6c6f0cb7..ec49c1c9 100644 --- a/problems/0020.有效的括号.md +++ b/problems/0020.有效的括号.md @@ -283,6 +283,31 @@ 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 +} +``` + C: ```C //辅助函数:判断栈顶元素与输入的括号是否为一对。若不是,则返回False @@ -324,6 +349,5 @@ bool isValid(char * s){ } ``` - -----------------------