May 25

Author: siddydutta

2025-05-May-LeetCoding-Challenge/Longest Palindrome by Concatenating Two Letter Words.py

@@ -0,0 +1,35 @@
+from collections import Counter
+
+
+class Solution:
+    def longestPalindrome(self, words: list[str]) -> int:
+        freq = Counter(words)
+        length, centered = 0, False
+
+        for word, count in freq.items():
+            if word[0] == word[1]:
+                if count % 2 == 0:
+                    length += count
+                else:
+                    length += (count - 1)
+                    centered = True
+            elif word[0] < word[1]:
+                length += 2 * min(count, freq[word[::-1]])
+
+        length += centered
+        return length * 2
+
+
+def main():
+    words = ['lc', 'cl', 'gg']
+    assert Solution().longestPalindrome(words) == 6
+
+    words = ['ab', 'ty', 'yt', 'lc', 'cl', 'ab']
+    assert Solution().longestPalindrome(words) == 8
+
+    words = ['cc', 'll', 'xx']
+    assert Solution().longestPalindrome(words) == 2
+
+
+if __name__ == '__main__':
+    main()

2025-05-May-LeetCoding-Challenge/README.md

@@ -28,7 +28,7 @@
 | May 22 | [3362. Zero Array Transformation III](https://leetcode.com/problems/zero-array-transformation-iii/) | Medium | Unsolved |
 | May 23 | [3068. Find the Maximum Sum of Node Values](https://leetcode.com/problems/find-the-maximum-sum-of-node-values/) | Hard | Unsolved |
 | May 24 | [2942. Find Words Containing Character](https://leetcode.com/problems/find-words-containing-character/) | Easy | Solved |
-| May 25 | []() |  |  |
+| May 25 | [2131. Longest Palindrome by Concatenating Two Letter Words](https://leetcode.com/problems/longest-palindrome-by-concatenating-two-letter-words/) | Medium | Solved |
 | May 26 | []() |  |  |
 | May 27 | []() |  |  |
 | May 28 | []() |  |  |
@@ -41,5 +41,5 @@
 | Level  | Problems | Solved | Unsolved |
 | ---    | --- | --- | --- |
 | Easy   | 6 | 6 | 0 |
-| Medium | 12 | 9 | 3 |
+| Medium | 13 | 10 | 3 |
 | Hard   | 5 | 1 | 4 |