Jun 11

Author: siddydutta

2025-06-June-LeetCoding-Challenge/Maximum Difference Between Even and Odd Frequency II.py

@@ -0,0 +1,46 @@
+from itertools import permutations
+
+
+class Solution:
+    def __get_status(self, n1: int, n2: int) -> int:
+        return ((n1 & 1) << 1) | (n2 & 1)
+
+    def maxDifference(self, s: str, k: int) -> int:
+        n = len(s)
+        ans = float('-inf')
+        for a, b in permutations('01234', 2):
+            best = [float('inf')] * 4
+            cnt_a, cnt_b = 0, 0
+            prev_a, prev_b = 0, 0
+            ptr1 = -1
+            for ptr2 in range(n):
+                cnt_a += s[ptr2] == a
+                cnt_b += s[ptr2] == b
+                while ptr2 - ptr1 >= k and cnt_b - prev_b >= 2:
+                    left_status = self.__get_status(prev_a, prev_b)
+                    best[left_status] = min(best[left_status], prev_a - prev_b)
+                    ptr1 += 1
+                    prev_a += s[ptr1] == a
+                    prev_b += s[ptr1] == b
+                right_status = self.__get_status(cnt_a, cnt_b)
+                if best[right_status ^ 0b10] != float('inf'):
+                    ans = max(ans, cnt_a - cnt_b - best[right_status ^ 0b10])
+        return ans
+
+
+def main():
+    s = '12233'
+    k = 4
+    assert Solution().maxDifference(s, k) == -1
+
+    s = '1122211'
+    k = 3
+    assert Solution().maxDifference(s, k) == 1
+
+    s = '110'
+    k = 3
+    assert Solution().maxDifference(s, k) == -1
+
+
+if __name__ == '__main__':
+    main()

2025-06-June-LeetCoding-Challenge/README.md

@@ -14,7 +14,7 @@
 | June 08 | [386. Lexicographical Numbers](https://leetcode.com/problems/lexicographical-numbers/) | Medium | Solved |
 | June 09 | [440. K-th Smallest in Lexicographical Order](https://leetcode.com/problems/k-th-smallest-in-lexicographical-order/) | Hard | Unsolved |
 | June 10 | [3442. Maximum Difference Between Even and Odd Frequency I](https://leetcode.com/problems/maximum-difference-between-even-and-odd-frequency-i/) | Easy | Solved |
-| June 11 | []() |  |  |
+| June 11 | [3445. Maximum Difference Between Even and Odd Frequency II](https://leetcode.com/problems/maximum-difference-between-even-and-odd-frequency-ii/) | Hard | Unsolved |
 | June 12 | []() |  |  |
 | June 13 | []() |  |  |
 | June 14 | []() |  |  |
@@ -41,4 +41,4 @@
 | ---    | --- | --- | --- |
 | Easy   | 1 | 1 | 0 |
 | Medium | 6 | 3 | 3 |
-| Hard   | 3 | 2 | 1 |
+| Hard   | 4 | 2 | 2 |