Merge pull request #992 from AlgorithmWithGod/khj20006

[20250927] BOJ / P2 / 인생은 B와 D 사이의 C다 / 권혁준

Author: ShinHeeEul

khj20006/202509/27 BOJ P2 인생은 B와 D 사이의 C다.md

@@ -0,0 +1,124 @@
+```java
+import java.io.*;
+import java.util.*;
+
+class IOController {
+	BufferedReader br;
+	BufferedWriter bw;
+	StringTokenizer st;
+
+	public IOController() {
+		br = new BufferedReader(new InputStreamReader(System.in));
+		bw = new BufferedWriter(new OutputStreamWriter(System.out));
+		st = new StringTokenizer("");
+	}
+
+	String nextLine() throws Exception {
+		String line = br.readLine();
+		st = new StringTokenizer(line);
+		return line;
+	}
+
+	String nextToken() throws Exception {
+		while (!st.hasMoreTokens())
+			nextLine();
+		return st.nextToken();
+	}
+
+	int nextInt() throws Exception {
+		return Integer.parseInt(nextToken());
+	}
+
+	long nextLong() throws Exception {
+		return Long.parseLong(nextToken());
+	}
+
+	double nextDouble() throws Exception {
+		return Double.parseDouble(nextToken());
+	}
+
+	void close() throws Exception {
+		bw.flush();
+		bw.close();
+	}
+
+	void write(String content) throws Exception {
+		bw.write(content);
+	}
+
+}
+
+public class Main {
+
+	static IOController io;
+
+	//
+
+	static int N;
+	static long B, D;
+	static List<Integer>[] tree;
+	static long[] s;
+	static long[][] dp;
+
+	public static void main(String[] args) throws Exception {
+
+		io = new IOController();
+
+		N = io.nextInt();
+		B = io.nextInt();
+		D = io.nextInt();
+		tree = new List[N+1];
+		s = new long[N+1];
+		dp = new long[N+1][35];
+		for(int i=1;i<=N;i++) tree[i] = new ArrayList<>();
+
+		for(int i=1;i<N;i++) {
+			int a = io.nextInt();
+			int b = io.nextInt();
+			tree[a].add(b);
+			tree[b].add(a);
+		}
+
+		dfs(1,0);
+
+		long ans = Long.MAX_VALUE;
+		for(int i=0;i<35;i++) {
+			ans = Math.min(ans, dp[1][i]);
+		}
+		io.write(ans + "\n");
+
+		io.close();
+
+	}
+
+	static void dfs(int n, int p) {
+		s[n] = 1;
+		int children = 0;
+		for(int i:tree[n]) if(i != p) {
+			dfs(i, n);
+			s[n] += s[i];
+			children++;
+		}
+		dp[n][0] = D*(s[n] - 1);
+		for(int h=1;h<35;h++) {
+			if(children == 0) dp[n][h] = B*((1L<<(h+1)) - 2);
+			else {
+				List<long[]> tmp = new ArrayList<>();
+				for(int i:tree[n]) if(i != p) {
+					tmp.add(new long[]{D*s[i] - dp[i][h-1], i});
+				}
+				Collections.sort(tmp, (a,b) -> Long.compare(b[0],a[0]));
+				if(children == 1) {
+					dp[n][h] = dp[(int)tmp.get(0)[1]][h-1] + B*((1L<<h)-1);
+				}
+				else {
+					dp[n][h] = dp[(int)tmp.get(0)[1]][h-1] + dp[(int)tmp.get(1)[1]][h-1];
+					for(int i=2;i<tmp.size();i++) dp[n][h] += D*s[(int)tmp.get(i)[1]];
+				}
+			}
+			dp[n][h] = Math.min(dp[n][h], D*(s[n]-1) + B*((1L<<(h+1))-2));
+		}
+	}
+
+}
+```