Bracket.java

package hacked.puzzles.story.cyber_attack.match;

import java.util.ArrayList;

public enum Bracket {
	CLOSE {
		@Override
		public String toString() {
			return ")";
		}
	},
	OPEN {
		@Override
		public String toString() {
			return "(";
		}
	};
	public static ArrayList<Bracket> generate(int n) {
		final ArrayList<Bracket> pattern = new ArrayList<>();
		while (n > 0) {
			pattern.add(0, n % 2 == 0 ? CLOSE : OPEN);
			n -= n % 2;
			n /= 2;
		}
		return pattern;
	}

	public static boolean hacked(ArrayList<Bracket> input) {
		input = new ArrayList<>(input);
		if (input.size() % 2 != 0) {
			return false;
		}
		while (input.size() > 0) {
			int var_a = 0;
			while (var_a < input.size() && input.get(var_a) != CLOSE) {
				++var_a;
			}
			if (var_a == 0 || var_a == input.size()) {
				return false;
			}
			input.remove(var_a);
			input.remove(var_a - 1);
		}
		assert input.size() == 0;
		return true;
	}

	public static void main(final String[] args) {
		for (int i = 0; i < 64; i++) {
			final ArrayList<Bracket> input = generate(i);
			if (hacked(input)) {
				final StringBuilder sb = new StringBuilder();
				sb.append('[');
				for (int j = 0; j < input.size(); ++j) {
					if (j != 0) {
						sb.append(',');
						sb.append(' ');
					}
					sb.append(input.get(j).toString());
				}
				sb.append(']');
				System.out.println(sb.toString());
			}
		}
	}
}