#![feature(core, unicode)]
extern crate core;
extern crate unicode;

use core::iter::repeat;
use core::str::StrExt;
use unicode::char::CharExt;

fn rec_can_make_word(index: usize, word: &str, blocks: &[&str], used: &mut[bool]) -> bool {
	let c = word.char_at(index).to_uppercase();
	for i in range(0, blocks.len()) {
		if !used[i] && blocks[i].chars().any(|s| s == c) {
			used[i] = true;
			if index == 0 || rec_can_make_word(index - 1, word, blocks, used) {
				return true;
			}
			used[i] = false;
		}
	}
	false
}
			
fn can_make_word(word: &str, blocks: &[&str]) -> bool {
	return rec_can_make_word(word.char_len() - 1, word, blocks, repeat(false).take(blocks.len()).collect::<Vec<_>>().as_mut_slice());
}

fn main() {
	let blocks = [("BO"), ("XK"), ("DQ"), ("CP"), ("NA"), ("GT"), ("RE"), ("TG"), ("QD"), ("FS"), ("JW"), ("HU"), ("VI"), ("AN"), ("OB"), ("ER"), ("FS"), ("LY"), ("PC"), ("ZM")];	
	let words = ["A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"];
	for word in words.iter() {
		println!("{} -> {}", word, can_make_word(word.as_slice(), blocks.as_slice()))
	}
}