docs: add Longest Repeating Character Replacement

Author: dukeluo

README.md

@@ -35,6 +35,7 @@ https://neetcode.io/roadmap
 | 981 | [Time Based Key-Value Store](https://leetcode.com/problems/time-based-key-value-store/)                                         | Medium     | [TypeScript](./TypeScript/981.time-based-key-value-store.ts)                   | Binary Search    |
 | 121 | [Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/)                               | Easy       | [TypeScript](./TypeScript/121.best-time-to-buy-and-sell-stock.ts)              | Sliding Window   |
 | 3   | [Longest Substring Without Repeating Characters](https://leetcode.com/problems/longest-substring-without-repeating-characters/) | Medium     | [TypeScript](./TypeScript/3.longest-substring-without-repeating-characters.ts) | Sliding Window   |
+| 424 | [Longest Repeating Character Replacement](https://leetcode.com/problems/longest-repeating-character-replacement/)               | Medium     | [TypeScript](./TypeScript/424.longest-repeating-character-replacement.ts)      | Sliding Window   |
 
 ### Others
 

TypeScript/424.longest-repeating-character-replacement.ts

@@ -0,0 +1,39 @@
+function characterReplacement(s: string, k: number): number {
+  const map = new Map<string, number>();
+  let left = 0;
+  let right = 0;
+  let result = 0;
+
+  while (right < s.length) {
+    map.set(s[right], (map.get(s[right]) ?? 0) + 1);
+    while (right - left + 1 - Math.max(...map.values()) > k) {
+      map.set(s[left], map.get(s[left])! - 1);
+      left++;
+    }
+    result = Math.max(result, right - left + 1);
+    right++;
+  }
+
+  return result;
+}
+
+function characterReplacement2(s: string, k: number): number {
+  const map = new Map<string, number>();
+  let left = 0;
+  let right = 0;
+  let result = 0;
+  let maxf = 0;
+
+  while (right < s.length) {
+    map.set(s[right], (map.get(s[right]) ?? 0) + 1);
+    maxf = Math.max(maxf, map.get(s[right])!);
+    while (right - left + 1 - maxf > k) {
+      map.set(s[left], map.get(s[left])! - 1);
+      left++;
+    }
+    result = Math.max(result, right - left + 1);
+    right++;
+  }
+
+  return result;
+}