Method main

src/class185/Code07_HideSeek1.java:374–415

(String[] args)

	}

	public static void main(String[] args) throws Exception {
		FastReader in = new FastReader();
		PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
		n = in.nextInt();
		for (int i = 1, u, v; i < n; i++) {
			u = in.nextInt();
			v = in.nextInt();
			addEdge(u, v);
			addEdge(v, u);
		}
		// dfs1(1, 0);
		// dfs2(1, 1);
		dfs3(1, 0);
		dfs4(1, 1);
		centroidTree(getCentroid(1, 0), 0);
		prepare();
		m = in.nextInt();
		int blackCnt = n;
		char op;
		for (int i = 1, x; i <= m; i++) {
			op = in.nextChar();
			if (op == 'C') {
				x = in.nextInt();
				black[x] = !black[x];
				if (black[x]) {
					off(x);
					blackCnt++;
				} else {
					on(x);
					blackCnt--;
				}
			} else {
				if (blackCnt <= 1) {
					out.println(blackCnt - 1);
				} else {
					out.println(maxDist.first());
				}
			}
		}
		out.flush();
		out.close();
	}

	// 读写工具类
	static class FastReader {