Merge pull request #829 from AlgorithmWithGod/khj20006

[20250906] BOJ / G2 / 멀지만 가까운 사이 / 권혁준

Author: ShinHeeEul

khj20006/202509/06 BOJ G2 멀지만 가까운 사이.md

@@ -0,0 +1,111 @@
+```java
+import java.util.*;
+import java.io.*;
+
+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 List<int[]>[] graph;
+	static List<Integer> list;
+
+	public static void main(String[] args) throws Exception {
+
+		io = new IOController();
+
+		N = io.nextInt();
+		list = new ArrayList<>();
+		graph = new List[N+1];
+		for(int i=1;i<=N;i++) graph[i] = new ArrayList<>();
+		for(int i=1;i<N;i++) {
+			int a = io.nextInt();
+			int b = io.nextInt();
+			int c = io.nextInt();
+			graph[a].add(new int[]{b,c});
+			graph[b].add(new int[]{a,c});
+		}
+
+		Queue<int[]> q = new ArrayDeque<>();
+		boolean[] vis = new boolean[N+1];
+		q.offer(new int[]{1,0});
+		vis[1] = true;
+		while(!q.isEmpty()) {
+			int[] cur = q.poll();
+			int n = cur[0], v = cur[1];
+			list.add(v);
+			for(int[] e:graph[n]) if(!vis[e[0]]) {
+				vis[e[0]] = true;
+				q.offer(new int[]{e[0],v^e[1]});
+			}
+		}
+		Collections.sort(list);
+
+		long ans = 0, cnt = 1;
+		int prev = list.get(0);
+		for(int i=1;i<N;i++) {
+			int v = list.get(i);
+			if(v != prev) {
+				ans += cnt*(cnt-1)/2;
+				cnt = 0;
+			}
+			cnt++;
+			prev = v;
+		}
+		ans += cnt*(cnt-1)/2;
+
+		io.write(ans + "\n");
+
+		io.close();
+
+	}
+
+}
+```