package LeetCode;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Stack;

public class LC_20 {
    public static void main(String[] args) {
        System.out.println(isValid("]"));
    }

    public static boolean isValid(String s) {
        Stack<Character> st = new Stack<>();
        HashMap<Character, Character> map = new HashMap<>();
        map.put('(', ')');
        map.put('{', '}');
        map.put('[', ']');
        for (int i = 0; i < s.length(); i++) {
            if (map.containsKey(s.charAt(i))) st.add(s.charAt(i));
            else if (!st.isEmpty() && s.charAt(i) == map.get(st.peek())) st.pop();
            else return false;
        }
        return st.isEmpty();
    }
}