Problem of The Day: Find First Palindromic String in the Array

Problem Statement

Intuition

My initial thought is to iterate through the words, checking each one for palindrome property, and returning the first palindrome encountered.

Approach

I’ll loop through each word in the list and use string slicing (word[::-1]) to reverse the word. If the reversed word is the same as the original, it’s a palindrome, and I’ll return it. If no palindrome is found, I’ll return an empty string.

Complexity

• Time complexity: O(m * n) where n is the number of words and mmm is the maximum length of a word. This is because, for each word, we may need to compare up to m characters.

• Space complexity: O(1) as we are not using any additional space that scales with the input.

Code

class Solution:
    def firstPalindrome(self, words: List[str]) -> str:
        for word in words:
            if word == word[::-1]:
                return word
        return ""

Other Approach: Check for Palindrome using two pointers

class Solution:
    def is_palindromic(self, word):
        l, r = 0, len(word) - 1
        while l < r:
            if word[l] != word[r]: return False
            l += 1
            r -= 1
        return True

    def firstPalindrome(self, words: List[str]) -> str:
        for word in words:
            if self.is_palindromic(word):
                return word
        return ""