diff --git "a/ksinji/202512/18 BOJ A\354\231\200 B.md" "b/ksinji/202512/18 BOJ A\354\231\200 B.md"
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+++ "b/ksinji/202512/18 BOJ A\354\231\200 B.md"	
@@ -0,0 +1,39 @@
+```java
+import java.io.*;
+
+public class Main {
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        String s = br.readLine();
+        String t = br.readLine();
+       
+        char[] a = t.toCharArray();
+        int l = 0;
+        int r = a.length - 1;
+        boolean dir = false;
+
+        while (r - l + 1 > s.length()) {
+            char last = dir ? a[l] : a[r];
+            if (last == 'A') {
+                if (dir) l++;
+                else r--;
+            } else {
+                if (dir) l++;
+                else r--;
+                dir = !dir;
+            }
+        }
+
+        for (int i = 0; i < s.length(); i++) {
+            char c = dir ? a[r - i] : a[l + i];
+            if (c != s.charAt(i)) {
+                System.out.print(0);
+                return;
+            }
+        }
+
+        System.out.print(1);
+    }
+}
+```
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