README_EN.md

2108. Find First Palindromic String in the Array

中文文档

Description

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.

Solutions

Python3

class Solution:
    def firstPalindrome(self, words: List[str]) -> str:
        def check(s):
            i, j = 0, len(s) - 1
            while i < j:
                if s[i] != s[j]:
                    return False
                i += 1
                j -= 1
            return True

        for word in words:
            if check(word):
                return word
        return ''

Java

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

    private boolean check(String s) {
        for (int i = 0, j = s.length() - 1; i < j; ++i, --j) {
            if (s.charAt(i) != s.charAt(j)) {
                return false;
            }
        }
        return true;
    }
}

C++

class Solution {
public:
    string firstPalindrome(vector<string>& words) {
        for (auto& word : words)
            if (check(word)) return word;
        return "";
    }

    bool check(string s) {
        for (int i = 0, j = s.size() - 1; i < j; ++i, --j)
            if (s[i] != s[j]) return false;
        return true;
    }
};

Go

func firstPalindrome(words []string) string {
	check := func(s string) bool {
		for i, j := 0, len(s)-1; i < j; i, j = i+1, j-1 {
			if s[i] != s[j] {
				return false
			}
		}
		return true
	}

	for _, word := range words {
		if check(word) {
			return word
		}
	}
	return ""
}

TypeScript

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