module BalancedBrackets {
    Boolean balanced(String text) {
        Int depth = 0;
        for (Char ch : text) {
            switch (ch, depth) {
            case ('[', _):
                ++depth;
                break;
            case (']', 0):
                return False;
            case (']', _):
                --depth;
                break;
            }
        }
        return depth==0;
    }

    @Inject Console console;
    void run() {
        String[] tests =
            [
            "[]",
            "[][]",
            "[]][[]",
            "[[[]][]]",
            "][[[[]][]]",
            "[[[]][[]][]]",
            "]][[]][[[[][]]",
            "[[]]]][]][[][[[]",
            ];
        Int longest = tests.map(s -> s.size).reduce(0, (max, len) -> max.maxOf(len));
        for (String test : tests) {
            console.print($"{test}{' ' * (longest-test.size)} {balanced(test) ? "OK" : "NOT OK"}");
        }
    }
}