From 928f1ba6359e2680987a2fddc84f935b68ffc253 Mon Sep 17 00:00:00 2001
From: LiiNi-coder <97495437+LiiNi-coder@users.noreply.github.com>
Date: Fri, 5 Sep 2025 23:51:53 +0900
Subject: [PATCH] =?UTF-8?q?[20250905]=20BOJ=20/=20G5=20/=20=EC=86=9C=20?=
 =?UTF-8?q?=EC=82=AC=EC=9D=B4=20=EC=88=98=EC=97=B4=20/=20=EC=9D=B4?=
 =?UTF-8?q?=EC=9D=B8=ED=9D=AC?=
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---
 ...4\354\235\264 \354\210\230\354\227\264.md" | 72 +++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100644 "LiiNi-coder/202509/05 BOJ \354\206\234 \354\202\254\354\235\264 \354\210\230\354\227\264.md"

diff --git "a/LiiNi-coder/202509/05 BOJ \354\206\234 \354\202\254\354\235\264 \354\210\230\354\227\264.md" "b/LiiNi-coder/202509/05 BOJ \354\206\234 \354\202\254\354\235\264 \354\210\230\354\227\264.md"
new file mode 100644
index 00000000..31d2d21d
--- /dev/null
+++ "b/LiiNi-coder/202509/05 BOJ \354\206\234 \354\202\254\354\235\264 \354\210\230\354\227\264.md"	
@@ -0,0 +1,72 @@
+```java
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.Arrays;
+import java.util.StringTokenizer;
+
+public class Main {
+    private static BufferedReader br;
+    private static int N;
+    private static int[] X;
+    private static int[] answer;
+    private static boolean[] used;
+    private static boolean found;
+
+    public static void main(String[] args) throws IOException {
+        br = new BufferedReader(new InputStreamReader(System.in));
+        N = Integer.parseInt(br.readLine());
+        X = new int[N];
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        for (int i = 0; i < N; i++) {
+            X[i] = Integer.parseInt(st.nextToken());
+        }
+        Arrays.sort(X);
+        answer = new int[2 * N];
+        Arrays.fill(answer, -1);
+        used = new boolean[N];
+
+        backtrack(0);
+
+        if (!found) {
+            System.out.println(-1);
+        }
+    }
+
+    private static void backtrack(int idx) {
+        if (found)
+            return;
+
+
+        if (idx == 2 * N) {
+            StringBuilder sb = new StringBuilder();
+            for (int v : answer) sb.append(v).append(' ');
+            System.out.println(sb.toString());
+            found = true;
+            return;
+        }
+        if (answer[idx] != -1) {
+            backtrack(idx + 1);
+            return;
+        }
+
+        for (int i = 0; i < N; i++) {
+            if (used[i])
+                continue;
+            int val = X[i];
+            int secIdx = idx + val + 1;
+            if (secIdx >= 2 * N || answer[secIdx] != -1) continue;
+
+            answer[idx] = val;
+            answer[secIdx] = val;
+            used[i] = true;
+
+            backtrack(idx + 1);
+
+            answer[idx] = -1;
+            answer[secIdx] = -1;
+            used[i] = false;
+        }
+    }
+}
+```