diff --git "a/lkhyun/202509/21 BOJ G4 \354\210\230\353\223\244\354\235\230 \355\225\251 4.md" "b/lkhyun/202509/21 BOJ G4 \354\210\230\353\223\244\354\235\230 \355\225\251 4.md"
new file mode 100644
index 00000000..2845a2a3
--- /dev/null
+++ "b/lkhyun/202509/21 BOJ G4 \354\210\230\353\223\244\354\235\230 \355\225\251 4.md"	
@@ -0,0 +1,38 @@
+```java
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    static StringTokenizer st;
+    static int N,K;
+    static long[] A;
+    
+    public static void main(String[] args) throws IOException {
+        st = new StringTokenizer(br.readLine());
+        N = Integer.parseInt(st.nextToken());
+        K = Integer.parseInt(st.nextToken());
+
+        A = new long[N+1];
+        st = new StringTokenizer(br.readLine());
+        for (int i = 1; i <= N; i++) {
+            A[i] = A[i-1] + Integer.parseInt(st.nextToken());
+        }
+
+        Map<Long, Integer> SumCount = new HashMap<>();
+        long count = 0;
+        
+        SumCount.put(0L, 1);
+        
+        for (int j = 1; j <= N; j++) {
+            long target = A[j] - K;
+            count += SumCount.getOrDefault(target, 0);
+            
+            SumCount.put(A[j], SumCount.getOrDefault(A[j], 0) + 1);
+        }
+        bw.write(count + "\n");
+        bw.close();
+    }
+}
+```