diff --git a/code_study/Baekjoon/java/_12015.java b/code_study/Baekjoon/java/_12015.java
new file mode 100644
index 0000000..45a6104
--- /dev/null
+++ b/code_study/Baekjoon/java/_12015.java
@@ -0,0 +1,37 @@
+import java.util.*;
+
+public class _12015 {
+    public static void main(String args[]) {
+        Scanner sc = new Scanner(System.in);
+
+        int N = sc.nextInt();
+        int[] A = new int[N];
+        for(int i=0; i<N; i++) A[i] = sc.nextInt();
+
+        sc.close();
+
+        int[] LIS = new int[N];
+        int len = 0;
+        LIS[len++] = A[0];
+
+        for(int i=1; i<N; i++) {
+            int num = A[i];
+
+            if(LIS[len-1] < num) LIS[len++] = num;
+            else {
+                int left = 0, right = len-1;
+                int mid = (left + right) / 2;
+                while(left < right) {
+                    if(LIS[mid] < num) left = mid + 1;
+                    else right = mid;
+
+                    mid = (left + right) / 2;
+                }
+
+                LIS[mid] = num;
+            }
+        }
+
+        System.out.println(len);
+    }
+}
diff --git a/code_study/Baekjoon/python/2712.py b/code_study/Baekjoon/python/2712.py
new file mode 100644
index 0000000..27c18f3
--- /dev/null
+++ b/code_study/Baekjoon/python/2712.py
@@ -0,0 +1,22 @@
+import sys
+input = sys.stdin.readline
+
+def conv(s) :
+    num, unit = s.split()
+    num = float(num)
+    
+    if unit == "kg" :
+        return f"{num * 2.2046:.4f} lb"
+    elif unit == "lb" :
+        return f"{num * 0.4536:.4f} kg"
+    elif unit == "l" :
+        return f"{num * 0.2642:.4f} g"
+    else :
+        return f"{num * 3.7854:.4f} l"
+
+ans = []
+
+for _ in range(int(input())) :
+    ans.append(conv(input()))
+
+print("\n".join(ans))
\ No newline at end of file
diff --git a/code_study/Baekjoon/swift/11053.swift b/code_study/Baekjoon/swift/11053.swift
new file mode 100644
index 0000000..9acc4d4
--- /dev/null
+++ b/code_study/Baekjoon/swift/11053.swift
@@ -0,0 +1,22 @@
+func solv() {
+    guard let N = Int(readLine() ?? ""),
+          let a = readLine()
+    else { return }
+    
+    let A = a.split(separator: " ").compactMap{Int($0)}
+    guard A.count == N else { return }
+    
+    var dp = Array(repeating: 1, count: N)
+    
+    for i in 0..<N {
+        for j in 0..<i {
+            if A[i] > A[j] {
+                dp[i] = max(dp[i], dp[j] + 1)
+            }
+        }
+    }
+    
+    print(dp.max)
+}
+
+solv()
\ No newline at end of file