import java.util.ArrayDeque;
import java.util.Deque;
import java.util.Scanner;

import static java.lang.System.in;
import static java.lang.System.out;

/*
 *
 *
Use a stack to check parentheses, balanced and nesting
 *  The parentheses are: (), [] and {}
 *
 *  See:
 *  - UseAStack
 *
 */

public class Ex3CheckParen {


    public static void main(String[] args) {
        new Ex3CheckParen().program();
    }


    void program() {
        // All should be true
        out.println(checkParentheses("()"));

        out.println(checkParentheses("(()())"));

        out.println(!checkParentheses("(()))")); // Unbalanced

        out.println(!checkParentheses("((())")); // Unbalanced


        out.println(checkParentheses("({})"));

        out.println(!checkParentheses("({)}"));  // Bad nesting

        out.println(checkParentheses("({} [()] ({}))"));

        out.println(!checkParentheses("({} [() ({)})"));  // Unbalanced and bad nesting

    }


    // This is interesting because have to return, but what if no match?!?

    boolean checkParentheses(String str) {
        Deque<Character> stack = new ArrayDeque<>();

        String k = "({[";
        String s = ")]}";
        for (int i = 0; i < str.length(); i++) {
            if (k.contains(String.valueOf(str.charAt(i)))) {
                stack.push(str.charAt(i));
            } else if (s.contains(String.valueOf(str.charAt(i)))) {

                if (matching(stack.peek()) == str.charAt(i)) {
                    return true;
                }
            } else{
                return false;
            }
        }
        return false;
    }



    char matching(char ch) {
        //char c =  must initialize but to what?!

        switch (ch) {
            case ')':
                return '('; // c = '('

            case ']':
                return '[';

            case '}':
                return '{';

            default:
                // return c;

                throw new IllegalArgumentException("No match found");
        }
    }
}