[20251213] BOJ / G5 / 4와 7 / 설진영

Author: llIllIllIllIllIllIllIllI

Seol-JY/202512/13 BOJ G5 4와 7.md

@@ -0,0 +1,24 @@
+```java
+import java.io.*;
+
+public class Main {
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        long k = Long.parseLong(br.readLine().trim());
+        
+        long n = k + 1;
+        
+        StringBuilder sb = new StringBuilder();
+        while (n > 1) {
+            if (n % 2 == 0) {
+                sb.append('4');
+            } else {
+                sb.append('7');
+            }
+            n /= 2;
+        }
+        
+        System.out.println(sb.reverse().toString());
+    }
+}
+```