diff --git a/code_study/Baekjoon/java/_9251.java b/code_study/Baekjoon/java/_9251.java
new file mode 100644
index 0000000..c9acc59
--- /dev/null
+++ b/code_study/Baekjoon/java/_9251.java
@@ -0,0 +1,25 @@
+import java.util.*;
+
+public class _9251 {
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        String s1 = sc.nextLine().trim();
+        String s2 = sc.nextLine().trim();
+        sc.close();
+
+        int l1 = s1.length(), l2 = s2.length();
+        int[][] lcs = new int[l1+1][l2+1];
+        
+        for(int i=1; i<=l1; i++) {
+            for(int j=1; j<=l2; j++) {
+                if(s1.charAt(i-1) == s2.charAt(j-1)) {
+                    lcs[i][j] = lcs[i-1][j-1] + 1;
+                }
+                else {
+                    lcs[i][j] = Math.max(lcs[i-1][j], lcs[i][j-1]);
+                }
+            }
+        }
+        System.out.println(lcs[l1][l2]);
+    }
+}
diff --git a/code_study/Baekjoon/swift/9251.swift b/code_study/Baekjoon/swift/9251.swift
new file mode 100644
index 0000000..4f2b501
--- /dev/null
+++ b/code_study/Baekjoon/swift/9251.swift
@@ -0,0 +1,21 @@
+if let s1 = readLine(), let s2 = readLine() {
+    let arr1: [Character] = Array(s1)
+    let arr2: [Character] = Array(s2)
+    let l1: Int = arr1.count
+    let l2: Int = arr2.count
+    var dp: [[Int]] = Array(repeating: Array(repeating:0, count: l2+1), count : l1+1)
+
+    for i in 1...l1 {
+        let c1: Character = arr1[i-1]
+        for j in 1...l2 {
+            let c2: Character = arr2[j-1]
+            if c1==c2 {
+                dp[i][j] = dp[i-1][j-1]+1
+            }
+            else {
+                dp[i][j] = max(dp[i-1][j], dp[i][j-1])
+            }
+        }
+    }
+    print(dp[l1][l2])
+}
\ No newline at end of file