Java实现-有效的括号序列

public class Solution {    /**     * @param s A string     * @return whether the string is a valid parentheses     */    public boolean isValidParentheses(String s) {        // Write your code here        if(s.length()==0){return false;}if(s.length()%2==1){return false;}Stack<Character> stack=new Stack<Character>();for(int i=0;i<s.length();i++){Character c=s.charAt(i);if(c!='('&&c!=')'&&c!='['&&c!=']'&&c!='{'&&c!='}'){return false;}if(c=='('||c=='{'||c=='['){stack.push(c);}else{if(stack.isEmpty()){return false;}if(c==')'){if(stack.peek()!='('){return false;}else{stack.pop();}}else if(c==']'){if(stack.peek()!='['){return false;}else{stack.pop();}}else{if(stack.peek()!='{'){return false;}else{stack.pop();}}}}if(!stack.isEmpty()){return false;}else{return true;}    }}