Merge pull request #425 from AlgorithmWithGod/khj20006

[20250709] BOJ / G1 / 서로소 / 권혁준

Author: ShinHeeEul

khj20006/202507/09 BOJ G1 서로소.md

@@ -0,0 +1,114 @@
+```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 long A, B, N;
+    static List<Long> list;
+
+    public static void main(String[] args) throws Exception {
+
+        io = new IOController();
+
+        int TC = io.nextInt();
+        for(int tc=1;tc<=TC;tc++) {
+            io.write("Case #" + tc + ": ");
+            init();
+            solve();
+        }
+
+        io.close();
+
+    }
+
+    public static void init() throws Exception {
+
+        A = io.nextLong();
+        B = io.nextLong();
+        N = io.nextLong();
+
+    }
+
+    static void solve() throws Exception {
+
+        list = new ArrayList<>();
+        for(long i=2;i*i<=N;i++) if(N%i == 0) {
+            while(N%i == 0) N/=i;
+            list.add(i);
+        }
+        if(N != 1) list.add(N);
+
+        io.write((f(B) - f(A-1)) + "\n");
+
+    }
+
+    static long f(long x) {
+
+        long res = x;
+        int size = list.size();
+        for(int i=1;i<(1<<size);i++) {
+            int cnt = 0;
+            long v = 1;
+            for(int j=0;j<size;j++) if((i & (1<<j)) != 0) {
+                v *= list.get(j);
+                cnt++;
+            }
+            if(cnt%2 == 1) res -= x/v;
+            else res += x/v;
+        }
+        return res;
+
+    }
+
+}
+```