Merge pull request #135 from AlgorithmWithGod/Seol-JY

[20250217] BOJ / 골드4 /  DSLR / 설진영

Author: ShinHeeEul

Seol-JY/202502/17 BOJ G4 DSLR.md

@@ -0,0 +1,72 @@
+```java
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    static class State {
+        int num;
+        String commands;
+        
+        State(int num, String commands) {
+            this.num = num;
+            this.commands = commands;
+        }
+    }
+    
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        int T = Integer.parseInt(br.readLine());
+
+        for (int i = 0; i < T; i++) {
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            int from = Integer.parseInt(st.nextToken());
+            int to = Integer.parseInt(st.nextToken());
+
+            String result = bfs(from, to);
+            System.out.println(result);
+        }
+    }
+
+    private static String bfs(int from, int to) {
+        Queue<State> queue = new LinkedList<>();
+        boolean[] visited = new boolean[10000];
+        
+        queue.offer(new State(from, ""));
+        visited[from] = true;
+        
+        while (!queue.isEmpty()) {
+            State current = queue.poll();
+            
+            if (current.num == to) {
+                return current.commands;
+            }
+            
+            int D = (current.num * 2) % 10000;
+            if (!visited[D]) {
+                visited[D] = true;
+                queue.offer(new State(D, current.commands + "D"));
+            }
+            
+            int S = current.num == 0 ? 9999 : current.num - 1;
+            if (!visited[S]) {
+                visited[S] = true;
+                queue.offer(new State(S, current.commands + "S"));
+            }
+            
+            int L = (current.num % 1000) * 10 + current.num / 1000;
+            if (!visited[L]) {
+                visited[L] = true;
+                queue.offer(new State(L, current.commands + "L"));
+            }
+            
+            int R = (current.num % 10) * 1000 + current.num / 10;
+            if (!visited[R]) {
+                visited[R] = true;
+                queue.offer(new State(R, current.commands + "R"));
+            }
+        }
+        
+        return "";
+    }
+}
+```