From 9a5e0410538ae1b8b6eb95962cd2512bb0b8642a Mon Sep 17 00:00:00 2001
From: SeungHyun Son <55887179+sonshn@users.noreply.github.com>
Date: Sat, 7 Nov 2026 12:45:55 +0900
Subject: [PATCH] to-lower-case solution

---
 to-lower-case/sonshn.java | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 to-lower-case/sonshn.java

diff --git a/to-lower-case/sonshn.java b/to-lower-case/sonshn.java
new file mode 100644
index 0000000000..030d6a92a0
--- /dev/null
+++ b/to-lower-case/sonshn.java
@@ -0,0 +1,21 @@
+/**
+ * 시간 복잡도: O(n)
+ * 공간 복잡도: O(n)
+ */
+class Solution {
+    public String toLowerCase(String s) {
+        StringBuilder sb = new StringBuilder();
+
+        for (int i = 0; i < s.length(); i++) {
+            char c = s.charAt(i);
+
+            if (c >= 'A' && c <= 'Z') {
+                c = (char) (c + 32);
+            }
+
+            sb.append(c);
+        }
+
+        return sb.toString();
+    }
+}