2108. Find First Palindromic String in the Array

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

Solution 1

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

Java Code
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class Solution {
    public String firstPalindrome(String[] words) {
        for (var w : words) {
            boolean ok = true;
            for (int i = 0, j = w.length() - 1; i < j && ok; ++i, --j) {
                if (w.charAt(i) != w.charAt(j)) {
                    ok = false;
                }
            }
            if (ok) {
                return w;
            }
        }
        return "";
    }
}

C++ Code
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class Solution {
public:
    string firstPalindrome(vector<string>& words) {
        for (auto& w : words) {
            bool ok = true;
            for (int i = 0, j = w.size() - 1; i < j; ++i, --j) {
                if (w[i] != w[j]) {
                    ok = false;
                }
            }
            if (ok) {
                return w;
            }
        }
        return "";
    }
};

Go Code
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func firstPalindrome(words []string) string {
	for _, w := range words {
		ok := true
		for i, j := 0, len(w)-1; i < j && ok; i, j = i+1, j-1 {
			if w[i] != w[j] {
				ok = false
			}
		}
		if ok {
			return w
		}
	}
	return ""
}

TypeScript Code
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function firstPalindrome(words: string[]): string {
    for (const word of words) {
        let left = 0;
        let right = word.length - 1;
        while (left < right) {
            if (word[left] !== word[right]) {
                break;
            }
            left++;
            right--;
        }
        if (left >= right) {
            return word;
        }
    }
    return '';
}

Rust Code
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impl Solution {
    pub fn first_palindrome(words: Vec<String>) -> String {
        for word in words.iter() {
            let s = word.as_bytes();
            let mut left = 0;
            let mut right = s.len() - 1;
            while left < right {
                if s[left] != s[right] {
                    break;
                }
                left += 1;
                right -= 1;
            }
            if left >= right {
                return word.clone();
            }
        }
        String::new()
    }
}

C Code
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char* firstPalindrome(char** words, int wordsSize) {
    for (int i = 0; i < wordsSize; i++) {
        int left = 0;
        int right = strlen(words[i]) - 1;
        while (left < right) {
            if (words[i][left] != words[i][right]) {
                break;
            }
            left++;
            right--;
        }
        if (left >= right) {
            return words[i];
        }
    }
    return "";
}