modify code

Author: algorithmzuo

src/class123/Code04.java

@@ -1,6 +1,6 @@
 package class123;
 
-// 测试链接 : https://www.luogu.com.cn/problem/P6419
+// 测试链接 : https://www.luogu.com.cn/problem/CF219D
 public class Code04 {
 
 }

src/class123/Code05.java

@@ -0,0 +1,141 @@
+package class123;
+
+// 树上聚会后送k个人的总时间最少
+// 测试链接 : https://www.luogu.com.cn/problem/P6419
+// 提交以下的code，提交时请把类名改成"Main"，可以通过所有用例
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.io.PrintWriter;
+import java.io.StreamTokenizer;
+import java.util.Arrays;
+
+public class Code05_Kamp {
+
+	public static int MAXN = 500001;
+
+	public static int n;
+
+	public static int k;
+
+	public static int[] people = new int[MAXN];
+
+	public static int[] head = new int[MAXN];
+
+	public static int[] next = new int[MAXN << 1];
+
+	public static int[] to = new int[MAXN << 1];
+
+	public static int[] weight = new int[MAXN << 1];
+
+	public static int cnt;
+
+	public static int[] size = new int[MAXN];
+
+	public static long[] incost = new long[MAXN];
+
+	public static long[] outcost = new long[MAXN];
+
+	public static long[] infirst = new long[MAXN];
+
+	public static long[] insecond = new long[MAXN];
+
+	public static long[] outfirst = new long[MAXN];
+
+	public static void build() {
+		cnt = 1;
+		Arrays.fill(people, 1, n + 1, 0);
+		Arrays.fill(head, 1, n + 1, 0);
+		Arrays.fill(incost, 1, n + 1, 0);
+		Arrays.fill(outcost, 1, n + 1, 0);
+		Arrays.fill(infirst, 1, n + 1, 0);
+		Arrays.fill(insecond, 1, n + 1, 0);
+		Arrays.fill(outfirst, 1, n + 1, 0);
+	}
+
+	public static void addEdge(int u, int v, int w) {
+		next[cnt] = head[u];
+		to[cnt] = v;
+		weight[cnt] = w;
+		head[u] = cnt++;
+	}
+
+	public static void dfs(int u, int f) {
+		size[u] = people[u];
+		for (int e = head[u], v, w; e != 0; e = next[e]) {
+			v = to[e];
+			w = weight[e];
+			if (v != f) {
+				dfs(v, u);
+				size[u] += size[v];
+				if (size[v] > 0) {
+					incost[u] += incost[v] + (long) w * 2;
+					if (infirst[u] < infirst[v] + w) {
+						insecond[u] = infirst[u];
+						infirst[u] = infirst[v] + w;
+					} else if (insecond[u] < infirst[v] + w) {
+						insecond[u] = infirst[v] + w;
+					}
+				}
+			}
+		}
+	}
+
+	public static void dp(int u, int f) {
+		for (int e = head[u], v, w; e != 0; e = next[e]) {
+			v = to[e];
+			w = weight[e];
+			if (v != f) {
+				if (k - size[v] > 0) {
+					outcost[v] = outcost[u] + (incost[u] - incost[v]);
+					if (size[v] == 0) {
+						outcost[v] += (long) w * 2;
+					}
+					if (infirst[v] + w == infirst[u]) {
+						outfirst[v] = Math.max(outfirst[u], insecond[u]) + w;
+					} else {
+						outfirst[v] = Math.max(outfirst[u], infirst[u]) + w;
+					}
+				}
+				dp(v, u);
+			}
+		}
+	}
+
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StreamTokenizer in = new StreamTokenizer(br);
+		PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
+		in.nextToken();
+		n = (int) in.nval;
+		build();
+		in.nextToken();
+		k = (int) in.nval;
+		for (int i = 1, u, v, w; i < n; i++) {
+			in.nextToken();
+			u = (int) in.nval;
+			in.nextToken();
+			v = (int) in.nval;
+			in.nextToken();
+			w = (int) in.nval;
+			addEdge(u, v, w);
+			addEdge(v, u, w);
+		}
+		for (int i = 1, u; i <= k; i++) {
+			in.nextToken();
+			u = (int) in.nval;
+			people[u]++;
+		}
+		dfs(1, 0);
+		dp(1, 0);
+		for (int i = 1; i <= n; i++) {
+			out.println(incost[i] + outcost[i] - Math.max(outfirst[i], infirst[i]));
+		}
+		out.flush();
+		out.close();
+		br.close();
+	}
+
+}