Method dfs2

src/class184/Code03_Courier1.java:141–161

(int cur, int fa, int di, int tr)

	// 收集信息迭代版
	public static void dfs2(int cur, int fa, int di, int tr) {
		stacksize = 0;
		push(cur, fa, di, tr, -1);
		while (stacksize > 0) {
			pop();
			if (e == -1) {
				tree[u] = t;
				dist[u] = d;
				e = head[u];
			} else {
				e = nxt[e];
			}
			if (e != 0) {
				push(u, f, d, t, e);
				int v = to[e];
				if (v != f) {
					push(v, u, d + weight[e], t, -1);
				}
			}
		}
	}

	public static int compute() {
		int ans = 1000000001;