leetcode 栈 括号匹配

https://oj.leetcode.com/problems/valid-parentheses/

遇到左括号入栈，遇到右括号出栈找匹配，为空或不匹配为空，

public class Solution {
    public boolean isValid(String s) {
        char c[]=s.toCharArray();
        Stack<Character> stack=new Stack<Character>();
        for(int i=0;i<s.length();i++)
        {
            if(c[i]=='('||c[i]=='['||c[i]=='{')stack.push(c[i]);
            else
            {
                if(stack.isEmpty()) return false;
                char c2=stack.peek();
                if(c[i]==')'&&c2=='(') stack.pop();
                else if(c[i]==']'&&c2=='[') stack.pop();
                else if(c[i]=='}'&&c2=='{') stack.pop();
                else return false;
            }

        }
        if(stack.isEmpty())
        {
        return true;
        }
        return false;

        }

}