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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.io.*;
  6.  
  7. /* Name of the class has to be "Main" only if the class is public. */
  8. class Ideone
  9. {
  10. 	public static void main(String[] args) {
  11.         System.out.println("enter the sequence of brackets:");
  12.         Scanner in = new Scanner(System.in);
  13.         //String s = in.nextLine();
  14.         String s = "((({{{[[[]]]}}})))";
  15.         String s2 = "(([{{{[[[]]]}}})))";
  16.         System.out.println(s + " is " + new Parentheses().isBalanced(s));
  17.         System.out.println(s2 + " is " + new Parentheses().isBalanced(s2));
  18.     }
  19. }
  20. class Parentheses {
  21.     private static final char LEFT_PAREN = '(';
  22.     private static final char RIGHT_PAREN = ')';
  23.     private static final char LEFT_BRACE = '{';
  24.     private static final char RIGHT_BRACE = '}';
  25.     private static final char LEFT_BRACKET = '[';
  26.     private static final char RIGHT_BRACKET = ']';
  27.  
  28.     public static boolean isBalanced(String s) {
  29.         Stack<Character> stack = new Stack<Character>();
  30.         for (int i = 0; i < s.length(); i++) {
  31.             if (s.charAt(i) == LEFT_PAREN) stack.push(LEFT_PAREN);
  32.             if (s.charAt(i) == LEFT_BRACE) stack.push(LEFT_BRACE);
  33.             if (s.charAt(i) == LEFT_BRACKET) stack.push(LEFT_BRACKET);
  34.  
  35.             if (s.charAt(i) == RIGHT_PAREN) {
  36.                 if (stack.isEmpty()) return false;
  37.                 if (stack.pop() != LEFT_PAREN) return false;
  38.             } else if (s.charAt(i) == RIGHT_BRACE) {
  39.                 if (stack.isEmpty()) return false;
  40.                 if (stack.pop() != LEFT_BRACE) return false;
  41.             } else if (s.charAt(i) == RIGHT_BRACKET) {
  42.                 if (stack.isEmpty()) return false;
  43.                 if (stack.pop() != LEFT_BRACKET) return false;
  44.             }
  45.         }
  46.         return stack.isEmpty();
  47.     }
  48. }
Success #stdin #stdout 0.09s 380736KB
comments (?)
stdin 
Standard input is empty
stdout 
enter the sequence of brackets:
((({{{[[[]]]}}}))) is true
(([{{{[[[]]]}}}))) is false
https://ideone.com/0ngwix
language:
Java (HotSpot 12)
created:
9 years ago
visibility:
public

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