[20250415] SWEA / D4 / 팩토리얼과 최대공약수 / 권혁준

khj20006/202504/15 SWEA D4 팩토리얼과 최대공약수.md

@@ -0,0 +1,77 @@
+```java
+
+import java.util.*;
+
+import java.io.*;
+
+public class Solution {
+
+    // IO field
+    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    static StringTokenizer st = new StringTokenizer("");
+
+    static void nextLine() throws Exception {st = new StringTokenizer(br.readLine());}
+    static String nextToken() throws Exception {
+        while(!st.hasMoreTokens()) nextLine();
+        return st.nextToken();
+    }
+    static int nextInt() throws Exception { return Integer.parseInt(nextToken()); }
+    static long nextLong() throws Exception { return Long.parseLong(nextToken()); }
+    static double nextDouble() throws Exception { return Double.parseDouble(nextToken()); }
+    static void bwEnd() throws Exception {bw.flush();bw.close();}
+
+
+    // Additional field
+
+    static long N, K;
+
+    // 
+
+    public static void main(String[] args) throws Exception {
+
+        int TC = nextInt();
+        for(int tc=1;tc<=TC;tc++) {
+
+            ready();
+            solve(tc);
+
+        }
+        bwEnd();
+
+    }
+
+    static void ready() throws Exception {
+
+    	N = nextInt();
+    	K = nextInt();
+
+    }
+
+    static void solve(int tc) throws Exception {
+        bw.write("#" + tc + " ");
+
+        long ans = 1;
+        for(long i=2;i*i<=K;i++) {
+        	long cnt = 0, d = 1;
+        	while(K%i == 0) {
+        		d *= i;
+        		K /= i;
+        		cnt++;
+        	}
+        	long ncnt = 0;
+        	for(long j=i;j<=N;j*=i) ncnt += N/j;
+        	while(cnt-ncnt>0) {
+        		cnt--;
+        		d /= i;
+        	}
+        	ans *= d;
+        }
+        if(N/K >= 1) ans *= K;
+        bw.write(ans + "\n");
+
+    }
+
+}
+
+```