From a63d9450b5f45658f7d2809dc0f5497d23bd6274 Mon Sep 17 00:00:00 2001
From: yuuuuuuyu <yuitfhk@gmail.com>
Date: Tue, 9 Dec 2025 14:48:58 +0900
Subject: [PATCH 1/2] best time to buy and sell stock

---
 .../YuuuuuuYu.java                            | 26 +++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 best-time-to-buy-and-sell-stock/YuuuuuuYu.java

diff --git a/best-time-to-buy-and-sell-stock/YuuuuuuYu.java b/best-time-to-buy-and-sell-stock/YuuuuuuYu.java
new file mode 100644
index 000000000..a771d5e16
--- /dev/null
+++ b/best-time-to-buy-and-sell-stock/YuuuuuuYu.java
@@ -0,0 +1,26 @@
+/**
+ * Runtime: 1ms
+ * Time Complexity: O(n)
+ *
+ * Memory: 94.08MB
+ * Space Complexity: O(1)
+ *
+ * Approach: 그리디 알고리즘
+ * - 주어진 prices 배열을 순회하며 최소 가격(min)을 갱신
+ */
+class Solution {
+    public int maxProfit(int[] prices) {
+        int maxProfit = 0;
+        int min = prices[0];
+
+        for (int i=1; i<prices.length; i++) {
+            if (min >= prices[i]) {
+                min = prices[i];
+            } else {
+                maxProfit = Math.max(maxProfit, prices[i]-min);
+            }
+        }
+
+        return maxProfit;
+    }
+}

From 53620e32d0269394cf4848f53d1d8a32b525117a Mon Sep 17 00:00:00 2001
From: yuuuuuuyu <yuitfhk@gmail.com>
Date: Tue, 9 Dec 2025 18:02:37 +0900
Subject: [PATCH 2/2] group anagrams

---
 group-anagrams/YuuuuuuYu.java | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 group-anagrams/YuuuuuuYu.java

diff --git a/group-anagrams/YuuuuuuYu.java b/group-anagrams/YuuuuuuYu.java
new file mode 100644
index 000000000..cfa1ae97b
--- /dev/null
+++ b/group-anagrams/YuuuuuuYu.java
@@ -0,0 +1,29 @@
+/**
+ * Runtime: 6ms
+ * Time Complexity: O(n x k log k)
+ * - n: 문자열 개수
+ * - k: 문자열 최대 길이
+ * - k log k: 각 문자열을 정렬하는 시간
+ *
+ * Memory: 49.30MB
+ * Space Complexity: O(n x k)
+ * - 최대 n개의 키-값
+ *
+ * Approach: 정렬된 문자열을 키로 사용해서 같은 애나그램끼리 그룹화
+ */
+class Solution {
+    public List<List<String>> groupAnagrams(String[] strs) {
+        Map<String, List<String>> anagramMap = new HashMap<>();
+
+        for (String str: strs) {
+            char[] chs = str.toCharArray();
+            Arrays.sort(chs);
+            String key = new String(chs);
+
+            anagramMap.computeIfAbsent(key, k -> new ArrayList<>())
+                    .add(str);
+        }
+
+        return new ArrayList<>(anagramMap.values());
+    }
+}