From a44e9d7bc84fe0b9bdee5f1a25a6e53c987b9b69 Mon Sep 17 00:00:00 2001
From: Dale Seo <5466341+DaleSeo@users.noreply.github.com>
Date: Wed, 22 Apr 2026 21:06:57 -0400
Subject: [PATCH 1/2] longest-repeating-character-replacement

---
 .../DaleSeo.rs                                | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 longest-repeating-character-replacement/DaleSeo.rs

diff --git a/longest-repeating-character-replacement/DaleSeo.rs b/longest-repeating-character-replacement/DaleSeo.rs
new file mode 100644
index 000000000..5f4584fc4
--- /dev/null
+++ b/longest-repeating-character-replacement/DaleSeo.rs
@@ -0,0 +1,27 @@
+// TC: O(n), where n is s.len()
+// SC: O(1), fixed 26-slot frequency array
+impl Solution {
+    pub fn character_replacement(s: String, k: i32) -> i32 {
+        let bytes = s.as_bytes();
+        let mut counts = [0i32; 26];
+        let mut start = 0usize;
+        let mut max_freq = 0i32;
+        let mut result = 0i32;
+
+        for end in 0..bytes.len() {
+            let idx = (bytes[end] - b'A') as usize;
+            counts[idx] += 1;
+            max_freq = max_freq.max(counts[idx]);
+
+            while (end - start + 1) as i32 - max_freq > k {
+                let left_idx = (bytes[start] - b'A') as usize;
+                counts[left_idx] -= 1;
+                start += 1;
+            }
+
+            result = result.max((end - start + 1) as i32);
+        }
+
+        result
+    }
+}

From d9f4ad000ebcccc7fcd27b16d30bd58fa1053b69 Mon Sep 17 00:00:00 2001
From: sangbeenmoon <moon.sb@navercorp.com>
Date: Fri, 24 Apr 2026 21:55:23 +0900
Subject: [PATCH 2/2] tried longest-repeating-char-replacement.

---
 .../sangbeenmoon.py                              | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
 create mode 100644 longest-repeating-character-replacement/sangbeenmoon.py

diff --git a/longest-repeating-character-replacement/sangbeenmoon.py b/longest-repeating-character-replacement/sangbeenmoon.py
new file mode 100644
index 000000000..ce5218128
--- /dev/null
+++ b/longest-repeating-character-replacement/sangbeenmoon.py
@@ -0,0 +1,16 @@
+class Solution:
+    def characterReplacement(self, s: str, k: int) -> int:
+        freq = {}
+        left = 0
+        ans = 0
+
+        for right in range(len(s)):
+            freq[s[right]] = freq.get(s[right], 0) + 1
+            
+            while (right - left + 1) - max(freq.values()) > k:
+                freq[s[left]] -= 1
+                left += 1
+            
+            ans = max(ans, right - left + 1)
+
+        return ans