Merge pull request #225 from AlgorithmWithGod/khj20006

[20250311] BOJ / P5 / 등산 마니아 / 권혁준

Author: ShinHeeEul

khj20006/202503/11 BOJ P5 등산 마니아.md

@@ -0,0 +1,79 @@
+```java
+
+import java.util.*;
+import java.io.*;
+
+
+class Main {
+	
+	// IO field
+	static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+	static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+	static StringTokenizer st;
+
+	static void nextLine() throws Exception {st = new StringTokenizer(br.readLine());}
+	static int nextInt() {return Integer.parseInt(st.nextToken());}
+	static long nextLong() {return Long.parseLong(st.nextToken());}
+	static void bwEnd() throws Exception {bw.flush();bw.close();}
+	
+	// Additional field
+	
+	static int N;
+	static List<Integer>[] V;
+	static long[] S;
+	static long ans = 0;
+	
+	public static void main(String[] args) throws Exception {
+			
+		ready();
+		solve();
+	
+		bwEnd();
+		
+	}
+	
+	static void ready() throws Exception{
+		
+		N = Integer.parseInt(br.readLine());
+		V = new List[N+1];
+		S = new long[N+1];
+		for(int i=1;i<=N;i++) V[i] = new ArrayList<>();
+		for(int i=1;i<N;i++) {
+			nextLine();
+			int a = nextInt(), b = nextInt();
+			V[a].add(b);
+			V[b].add(a);
+		}
+		
+	}
+	
+	static void solve() throws Exception{
+		
+		dfs(1,0,0);
+		bw.write(ans + "\n");
+		
+	}
+	
+	static void dfs(int n, int p, long d) {
+		S[n] = 1;
+		
+		for(int i:V[n]) if(i != p) {
+			dfs(i,n,d+1);
+			S[n] += S[i];
+			ans += S[i] * (N-S[i]);
+		}
+		
+		long temp = 0;
+		for(int i:V[n]) if(i != p) {
+			
+			temp += S[i] * (S[n]-S[i]-1); 
+			
+		}
+		temp = temp/2 + S[n]-1;
+		ans += temp * d;
+		
+	}
+	
+}
+
+```