Method addNum

src/class194/Code08_Tourists1.java:74–79

(int u, int num)

	}

	public static void addNum(int u, int num) {
		if (!maps.containsKey(u)) {
			maps.put(u, new TreeMap<>());
		}
		maps.get(u).put(num, maps.get(u).getOrDefault(num, 0) + 1);
	}

	public static void delNum(int u, int num) {
		int cnt = maps.get(u).get(num);