LeetCode Entry

2490. Circular Sentence

02.11.2024 easy 2024 kotlin rust

Are words circular?

2490. Circular Sentence easy blog post substack youtube deep-dive 1.webp

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Problem TLDR

Are words circular? #easy

Intuition

If the current char is space, check its surroundings. Don’t forget to check the first and the last letter of the entire sentence (that was what I forgot)

Approach

  • let’s do codegolf
  • windows() is nice
  • regex is slow (and a separate kind of language, but powerful if mastered)

Complexity

  • Time complexity: \(O(n)\)

  • Space complexity: \(O(1)\)

Code


    fun isCircularSentence(sentence: String) =
        sentence[0] == sentence.last() &&
        sentence.windowed(3).all { it[1] != ' ' || it[0] == it[2] }



    pub fn is_circular_sentence(sentence: String) -> bool {
        let bs = sentence.as_bytes();
        bs[0] == bs[bs.len() - 1] && bs.windows(3)
            .all(|w| w[1] != b' ' || w[0] == w[2])
    }



    bool isCircularSentence(string sentence) {
        return sentence[0] == sentence.back() &&
            !regex_search(sentence, regex("(.) (?!\\1)"));
    }