private static void enQueue(Set<String> dict, LinkedList<String> queue, String target, Map<String, Integer> map,
			int step) {
		if (dict == null || dict.isEmpty()) {
			return;
		}

		for (int i = 0; i < target.length(); i++) {
			for (char c = 'a'; c <= 'z'; c++) {
				StringBuilder sBuilder = new StringBuilder(target);
				if (sBuilder.charAt(i) == c) {
					continue;
				}
				sBuilder.setCharAt(i, c);
				if (dict.contains(sBuilder.toString())) {
					queue.addLast(sBuilder.toString());
					dict.remove(sBuilder.toString());
					map.put(sBuilder.toString(), step + 1);
				}
			}
		}
	}