Method getDist

src/class185/Code01_Wave1.java:185–187

(int x, int y)

	}

	public static int getDist(int x, int y) {
		return dep[x] + dep[y] - (dep[getLca(x, y)] << 1);
	}

	// 找重心需要计算子树大小的递归版，java会爆栈，C++不会
	public static void getSize1(int u, int fa) {