BracketsBalanceChecker

BracketsBalanceChecker.java

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

public class BracketsBalanceChecker {


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

    }

    static boolean isBalanced(String input) {

        char[] chars = input.toCharArray();
        Deque<Character> stack = new ArrayDeque<>();

        for (char ch : chars) {

            if (stack.isEmpty() && isCloser(ch)) {
                return false;
            }

            if (isCloser(ch)) {
                Character topChar = stack.peek();
                if (isCloser(ch, topChar)) {
                    stack.pop();
                } else {
                    return false;
                }
            } else {
                stack.push(ch);
            }
        }

        return stack.isEmpty();
    }

    private static boolean isCloser(char closeBracket) {
        return isCloser(closeBracket, '\0');
    }

    private static boolean isCloser(char closeBracket, char openBracket) {
        switch (closeBracket) {
            case ']':
                return openBracket == '[' || openBracket == '\0';
            case '}':
                return openBracket == '{' || openBracket == '\0';
            case ')':
                return openBracket == '(' || openBracket == '\0';
            default:
                return false;
        }
    }
}