[20260306] BOJ / G3 / 선물 전달 / 이준희

Author: JHLEE325

JHLEE325/202603/06 BOJ G3 선물 전달.md

@@ -0,0 +1,32 @@
+```java
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        int N = Integer.parseInt(br.readLine());
+
+        if (N == 1) {
+            System.out.println(0);
+            return;
+        }
+        if (N == 2) {
+            System.out.println(1);
+            return;
+        }
+
+        long[] dp = new long[N + 1];
+        long mod = 1000000000;
+
+        dp[1] = 0;
+        dp[2] = 1;
+
+        for (int i = 3; i <= N; i++) {
+            dp[i] = (i - 1) * (dp[i - 1] + dp[i - 2]) % mod;
+        }
+
+        System.out.println(dp[N]);
+    }
+}
+```