week8

Author: imgolden77

longest-repeating-character-replacement/imgolden77.py

@@ -22,4 +22,7 @@ def characterReplacement(self, s: str, k: int) -> int:
 
         return max_len
 
-    # O(N) time complexity and O(1) space complexity.
+    # O(N) time complexity and O(1) space complexity.
+
+
+    

palindromic-substrings/imgolden77.py

@@ -0,0 +1,25 @@
+class Solution:
+    def countSubstrings(self, s: str) -> int:
+        total_count = 0
+
+        def expand(left, right):
+            local_count = 0
+            while left>=0 and right< len(s) and s[left] == s[right]:
+            # while s[left] == s[right] and left>=0 and right< len(s) :
+            # The above line would cause index error if left or right go out of bounds
+                local_count += 1
+                left -= 1
+                right += 1
+            return local_count
+
+        for i in range(len(s)):
+            total_count += expand(i, i)
+            total_count += expand(i, i+1)
+        
+        return total_count
+    
+#Complexity Analysis
+#Time complexity: O(n^2) where n is the length of the input string s.
+#Space complexity: O(1) as we are using only a constant amount of extra space
+# Manacher's Algorithm can achieve O(n) time complexity for this problem.
+

reverse-bits/imgolden77.py

@@ -12,4 +12,5 @@ def reverseBits(self, n: int) -> int:
 
         return res
 
-# Complexity O(1) - Time: 32 iterations, Space: O(1) no extra space used
+# Complexity O(1) - Time: 32 iterations, Space: O(1) no extra space used
+