Merge pull request #1876 from AlgorithmWithGod/JHLEE325

[20260203] BOJ / G5 / 랭퍼든 수열쟁이야!! / 이준희

Author: ShinHeeEul

JHLEE325/202602/03 BOJ G5 랭퍼든 수열쟁이야!!.md

@@ -0,0 +1,57 @@
+```java
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    static int n, x, y, count;
+    static int[] arr;
+    static boolean[] used;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+
+        n = Integer.parseInt(st.nextToken());
+        x = Integer.parseInt(st.nextToken());
+        y = Integer.parseInt(st.nextToken());
+
+        arr = new int[2 * n + 1];
+        used = new boolean[n + 1];
+
+        int fixedNum = y - x - 1;
+        arr[x] = arr[y] = fixedNum;
+        used[fixedNum] = true;
+
+        check(1);
+
+        System.out.println(count);
+    }
+
+    static void check(int pos) {
+        if (pos == 2 * n + 1) {
+            count++;
+            return;
+        }
+
+        if (arr[pos] != 0) {
+            check(pos + 1);
+            return;
+        }
+
+        for (int i = 1; i <= n; i++) {
+            if (used[i]) continue;
+
+            if (pos + i + 1 <= 2 * n && arr[pos + i + 1] == 0) {
+                arr[pos] = arr[pos + i + 1] = i;
+                used[i] = true;
+
+                check(pos + 1);
+
+                arr[pos] = arr[pos + i + 1] = 0;
+                used[i] = false;
+            }
+        }
+    }
+}
+```