[20250807] BOJ / G5 / 4와 7 / 이종환

Author: 0224LJH

0224LJH/202508/7 BOJ 4와 7.md

@@ -0,0 +1,53 @@
+```java
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.*;
+
+
+public class Main {
+
+    static int target;
+    static List<Integer> list = new ArrayList<>();
+
+
+    public static void main(String[] args) throws IOException {
+        init();
+        process();
+        print();
+    }
+
+    private static void init() throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        target = Integer.parseInt(br.readLine());
+    }
+
+    private static void process() throws IOException {
+
+        int pos = 1;
+
+        while ( target > 0){
+            int pre = 1 << (pos-1);
+            int cur = 1 << pos;
+
+            if ( (target&pre) != 0){
+                target -= pre;
+                list.add(4);
+            }else{
+                target -= cur;
+                list.add(7);
+            }
+            pos++;
+
+
+        }
+    }
+
+
+    private static void print() {
+        for (int i = list.size()-1; i >= 0; i--){
+            System.out.print(list.get(i));
+        }
+    }
+}
+```