String[] dealHands(int numPlayers, String deck) throws Exception {
		int len = deck == null ? 0 : deck.length(),
			nums = 0,
			i = 0,
			j = 0;
		if(numPlayers < 1 || numPlayers > 50) {
			 throw new Exception("player's number must between 1 and 50.");
		}
		
		if(len > 50) {
			throw new Exception("deck's number must between 0 and 50.");
		}
		String[] cards = new String[numPlayers];
		for(; i < numPlayers; i++) {
			cards[i] = "";
		}
		i = 0;
		if(len == 0) {
			return cards;
		} else {
			nums = (int)Math.floor(len / numPlayers);
			len = numPlayers * nums;
			for(; i < nums; i++) {
				for(j = 0; j < numPlayers; j++) {
					cards[j] += String.valueOf(deck.charAt(i * numPlayers + j));
				}
			}
		}
		return cards;
	}