[20250614] BOJ / P3 / 교수님은 기다리지 않는다 / 권혁준

Author: oncsr

khj20006/202506/14 BOJ P3 교수님은 기다리지 않는다.md

@@ -0,0 +1,116 @@
+```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, M;
+    static int[] r;
+    static long[] c;
+
+    public static void main(String[] args) throws Exception {
+
+        io = new IOController();
+
+        while(true) {
+            N = io.nextInt();
+            M = io.nextInt();
+            if(N == 0) break;
+            init();
+            solve();
+        }
+
+        io.close();
+
+    }
+
+    static int f(int x) {
+        if(x == r[x]) return x;
+        int p = f(r[x]);
+        c[x] += c[r[x]];
+        return (r[x] = p);
+    }
+
+    public static void init() throws Exception {
+
+        r = new int[N+1];
+        for(int i=1;i<=N;i++) r[i] = i;
+        c = new long[N+1];
+
+    }
+
+    static void solve() throws Exception {
+
+        while(M-->0) {
+
+            char op = io.nextToken().charAt(0);
+            int a = io.nextInt(), b = io.nextInt();
+
+            if(op == '!') {
+                int w = io.nextInt();
+                int x = f(a), y = f(b);
+                if(x == y) continue;
+                c[y] = c[a]-c[b]+w;
+                r[y] = x;
+            }
+            else {
+                int x = f(a), y = f(b);
+                if(x != y) io.write("UNKNOWN\n");
+                else io.write((c[b] - c[a]) + "\n");
+            }
+
+        }
+
+    }
+
+}
+```