标签：
1 题目
Given a string containing just the characters ‘(‘, ‘)‘, ‘{‘, ‘}‘, ‘[‘ and ‘]‘, determine if the input string is valid.
The brackets must close in the correct order, "()" and "()[]{}" are all valid but "(]" and "([)]" are not.
2 思路
这题是真心比较简单了，一个栈就可以解决了。需要主要empty的情况。
3 代码：
public boolean isValid(String s) { Stack<Character> stack = new Stack<Character>(); for(Character ch : s.toCharArray()){ switch (ch) { case ‘(‘: case ‘[‘: case ‘{‘: stack.push(ch); break; case ‘)‘: if(stack.empty() || stack.peek() != ‘(‘) { return false; }else{ stack.pop(); } break; case ‘}‘: if(stack.empty() || stack.peek() != ‘{‘) { return false; }else{ stack.pop(); } break; case ‘]‘: if(stack.empty() || stack.peek() != ‘[‘) { return false; }else{ stack.pop(); } break; default: return false; } } return stack.empty(); }
[leetcode 20] Valid Parentheses
标签：
原文地址：http://www.cnblogs.com/lingtingvfengsheng/p/4779998.html
