feat(work): add longest‑repeating‑character‑replacement solution and rename variable in longest‑substring solution

work/Medium/Hash Table/3.longest-substring-without-repeating-characters.py

@@ -45,12 +45,12 @@ class Solution:
     def lengthOfLongestSubstring(self, s: str) -> int:
         left = 0
         ans = 0
-        seen = set()
+        window = set()
         for right, c in enumerate(s):
-            while c in seen:
-                seen.remove(s[left])
+            while c in window:
+                window.remove(s[left])
                 left += 1
-            seen.add(c)
+            window.add(c)
             ans = max(ans, right - left + 1)
 
         return ans