import ballerina/io;

function r(string word, string[] bl) returns boolean {
    if word == "" { return true; }
    int c = word[0].toBytes()[0] | 32;
   foreach int i in 0..<bl.length() {
        var b = bl[i];
        if c == (b.toBytes()[0] | 32) || c == (b.toBytes()[1] | 32) {
            bl[i] = bl[0];
            bl[0] = b;
            if r(word.substring(1), bl.slice(1)) { return true; }
            var t = bl[i];
            bl[i] = bl[0];
            bl[0] = t;
        }
   }
   return false;
}

function newSpeller(string blocks) returns (function(string) returns boolean) {
    string[] bl = re ` `.split(blocks);
    return function(string word) returns boolean {
        return r(word, bl);
    };
}

public function main() {
    var sp = newSpeller("BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM");
    foreach string word in ["A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"] {
        io:println(word.padEnd(7), " ", sp(word));
    }
}