2108. Find First Palindromic String in the Array

Problem

Given an array of strings words, return **the first *palindromic* string in the array**. If there is no such string, return **an empty string **"".

A string is palindromic if it reads the same forward and backward.

  Example 1:

Input: words = ["abc","car","ada","racecar","cool"]
Output: "ada"
Explanation: The first string that is palindromic is "ada".
Note that "racecar" is also palindromic, but it is not the first.

Example 2:

Input: words = ["notapalindrome","racecar"]
Output: "racecar"
Explanation: The first and only string that is palindromic is "racecar".

Example 3:

Input: words = ["def","ghi"]
Output: ""
Explanation: There are no palindromic strings, so the empty string is returned.

  Constraints:

• 1 <= words.length <= 100

• 1 <= words[i].length <= 100

• words[i] consists only of lowercase English letters.

Solution (Java)

class Solution {
    public static boolean isPalindrome(String s) {
        int len = s.length();
        for (int i = 0, j = len - 1; i <= len / 2 && j >= len / 2; i++, j--) {
            if (s.charAt(i) != s.charAt(j)) {
                return false;
            }
        }
        return true;
    }

    public String firstPalindrome(String[] words) {
        for (String word : words) {
            if (isPalindrome(word)) {
                return word;
            }
        }
        return "";
    }
}

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).