// https://www.hackerrank.com/challenges/java-stack/problem import java.util.Scanner; import java.util.Stack; public class JavaStack { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); while (scanner.hasNext()) { String input = scanner.next(); System.out.println(isBalanced(input)); } } private static boolean isBalanced(String string) { Stack brackets = new Stack<>(); for (int index = 0 ; index < string.length() ; index++) { char character = string.charAt(index); if (isOpeningBrace(character)) { brackets.push(character); } else if (isClosingBrace(character)) { if (brackets.isEmpty() || brackets.peek() != inverse(character)) { return false; } else { brackets.pop(); } } } return brackets.isEmpty(); } private static boolean isOpeningBrace(char character) { return character == '[' || character == '{' || character == '(' ; } private static boolean isClosingBrace(char character) { return character == ']' || character == '}' || character == ')' ; } private static char inverse(char bracket) { switch (bracket) { case ')' : return '('; case ']' : return '['; case '}' : return '{'; } return '-'; } }