标签：character color false [] div ring public boolean leetcode
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.
key:stack
peek():public E peek() 查看栈顶对象而不移除它。
public class Solution { public boolean isValid(String s) { Stack<Character> stack=new Stack<>(); for(int i=0;i<s.length();i++){ if(s.charAt(i)==‘(‘||s.charAt(i)==‘[‘||s.charAt(i)==‘{‘){ stack.push(s.charAt(i)); } else if(s.charAt(i)==‘)‘&&!stack.empty()&&stack.peek()==‘(‘){ stack.pop(); } else if(s.charAt(i)==‘]‘&&!stack.empty()&&stack.peek()==‘[‘){ stack.pop(); } else if(s.charAt(i)==‘}‘&&!stack.empty()&&stack.peek()==‘{‘){ stack.pop(); } else{ return false; } } return stack.empty(); } }
leetcode_20 Valid Parentheses(String)
标签：character color false [] div ring public boolean leetcode
原文地址：http://www.cnblogs.com/ytq1016/p/6803558.html
