[20251208] BOJ / G4 / 게임 / 김민진

Author: zinnnn37

zinnnn37/202512/8 BOJ G4 게임.md

@@ -0,0 +1,78 @@
+```java
+import java.io.*;
+import java.util.Arrays;
+import java.util.StringTokenizer;
+
+public class BJ_28423_게임 {
+
+    private static final BufferedReader  br = new BufferedReader(new InputStreamReader(System.in));
+    private static final BufferedWriter  bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    private static       StringTokenizer st;
+
+    private static int L, R, ans;
+    private static int[]     memo;
+    private static boolean[] checked;
+
+    public static void main(String[] args) throws IOException {
+        init();
+        sol();
+    }
+
+    private static void init() throws IOException {
+        st = new StringTokenizer(br.readLine());
+        L = Integer.parseInt(st.nextToken());
+        R = Integer.parseInt(st.nextToken());
+
+        ans = 0;
+        memo = new int[100_001];
+        checked = new boolean[100_001];
+        Arrays.fill(memo, 2);
+    }
+
+    private static void sol() throws IOException {
+        for (int i = L; i <= R; i++) {
+            ans += dfs(i);
+        }
+        bw.write(ans + "");
+        bw.flush();
+        bw.close();
+        br.close();
+    }
+
+    private static int dfs(int cur) {
+        if (memo[cur] != 2) {
+            return memo[cur];
+        }
+
+        if (checked[cur]) {
+            return memo[cur] = 0;
+        }
+
+        checked[cur] = true;
+
+        int A = 0;
+        int B = 1;
+
+        int tmp = cur;
+        while (tmp != 0) {
+            A += tmp % 10;
+            B *= tmp % 10;
+            tmp /= 10;
+        }
+
+        int res = Integer.parseInt(String.valueOf(A) + String.valueOf(B));
+
+        if (cur == res) {
+            memo[cur] = 1;
+        } else if (res > 100000) {
+            memo[cur] = -1;
+        } else {
+            memo[cur] = dfs(res);
+        }
+        checked[cur] = false;
+
+        return memo[cur];
+    }
+
+}
+```