[20250611] BOJ / P5 / 나무 위의 입자 / 권혁준

khj20006/202506/11 BOJ P5 나무 위의 입자.md

@@ -0,0 +1,128 @@
+```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("");
+    }
+
+    void nextLine() throws Exception {
+        st = new StringTokenizer(br.readLine());
+    }
+
+    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, M;
+    static List<Integer>[] V;
+    static int[] par;
+    static int[] OD, OU, ED, EU;
+
+    public static void main(String[] args) throws Exception {
+
+        io = new IOController();
+
+        init();
+        solve();
+
+        io.close();
+
+    }
+
+    public static void init() throws Exception {
+
+        N = io.nextInt();
+        M = io.nextInt();
+        V = new List[N+1];
+        for(int i=1;i<=N;i++) V[i] = new ArrayList<>();
+        for(int i=1;i<N;i++) {
+            int a = io.nextInt(), b = io.nextInt();
+            V[a].add(b);
+            V[b].add(a);
+        }
+
+        par = new int[N+1];
+        OD = new int[N+1];
+        OU = new int[N+1];
+        ED = new int[N+1];
+        EU = new int[N+1];
+
+    }
+
+    static void solve() throws Exception {
+
+        dfs1(1,0);
+        dfs2(1,0);
+
+        while(M-->0) {
+            int u = io.nextInt(), v = io.nextInt(), c = io.nextInt();
+            if(par[v] == u){
+                if(c == 0) io.write((OU[v] * OD[v] + EU[v] * ED[v]) + "\n");
+                else io.write((OU[v] * ED[v] + EU[v] * OD[v]) + "\n");
+            }
+            else{
+                if(c == 0) io.write((OU[u] * OD[u] + EU[u] * ED[u]) + "\n");
+                else io.write((OU[u] * ED[u] + EU[u] * OD[u]) + "\n");
+            }
+        }
+
+    }
+
+    static void dfs1(int n, int p) {
+        par[n] = p;
+        for(int i:V[n]) if(i != p) {
+            dfs1(i,n);
+            OD[n] += ED[i];
+            ED[n] += OD[i];
+        }
+        ED[n]++;
+    }
+
+    static void dfs2(int n, int p) {
+        if(n != 1) {
+            OU[n] = EU[p] + ED[p] - OD[n];
+            EU[n] = OU[p] + OD[p] - ED[n];
+        }
+        for(int i:V[n]) if(i != p) dfs2(i,n);
+    }
+
+}
+```