From 14eecaffba53e9b12748fbc0f8f7a281863d95b5 Mon Sep 17 00:00:00 2001
From: Jihyun Son <sonjh1217@naver.com>
Date: Mon, 18 Aug 2025 16:15:24 +0900
Subject: [PATCH 1/2] best time to buy and sell stock

---
 .../sonjh1217.swift                            | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
 create mode 100644 best-time-to-buy-and-sell-stock/sonjh1217.swift

diff --git a/best-time-to-buy-and-sell-stock/sonjh1217.swift b/best-time-to-buy-and-sell-stock/sonjh1217.swift
new file mode 100644
index 000000000..f03750ff8
--- /dev/null
+++ b/best-time-to-buy-and-sell-stock/sonjh1217.swift
@@ -0,0 +1,18 @@
+class Solution {
+    func maxProfit(_ prices: [Int]) -> Int {
+        var maxProfit = 0
+        var minPrice = prices[0]
+        
+        for i in (1..<prices.count) {
+            let profit = prices[i] - minPrice
+            maxProfit = max(profit, maxProfit)
+            minPrice = min(prices[i], minPrice)
+        }
+        
+        return maxProfit
+        
+        //시간복잡도 O(n)
+        //공간복잡도 O(1)
+    }
+}
+

From c1b622b5c3b4c0206e21c7275748cc89da38f37b Mon Sep 17 00:00:00 2001
From: Jihyun Son <sonjh1217@naver.com>
Date: Fri, 22 Aug 2025 23:49:44 +0900
Subject: [PATCH 2/2] group anagrams

---
 group-anagrams/sonjh1217.swift | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
 create mode 100644 group-anagrams/sonjh1217.swift

diff --git a/group-anagrams/sonjh1217.swift b/group-anagrams/sonjh1217.swift
new file mode 100644
index 000000000..7682acb6e
--- /dev/null
+++ b/group-anagrams/sonjh1217.swift
@@ -0,0 +1,18 @@
+class Solution {
+    func groupAnagrams(_ strs: [String]) -> [[String]] {
+        var stringsByCount = [[Int]: [String]]()
+        
+        strs.map { str in
+            var countsByAlphabet = Array(repeating: 0, count: 26)
+            for char in str.unicodeScalars {
+                countsByAlphabet[Int(char.value) - 97] += 1
+            }
+            stringsByCount[countsByAlphabet, default: []].append(str)
+        }
+        
+        return Array(stringsByCount.values)
+    }
+    //시간 O(n*L) L=string들의 평균 길이
+    //공간 O(n*L)
+}
+