括号匹配

public boolean isValid(String s){
        Stack<Character> stack = new Stack<>();
        Map<Character, Character> map = new HashMap<>();
        map.put('{', '}');
        map.put('(', ')');
        map.put('[', ']');
        for(char c:s.toCharArray()){
            if(c=='('||c=='{'||c=='['){
                stack.push(c);
            }else{
                if(stack.isEmpty()||stack.peek()!=map.get(c)){
                    return false;
                }else{
                    stack.pop();
                }
            }
        }
        return stack.isEmpty();
    }