Introduction

In this blog post, we will explore how to solve the LeetCode problem "2490" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

A sentence is a list of words that are separated by a single space with no leading or trailing spaces. For example, "Hello World", "HELLO", "hello world hello world" are all sentences. Words consist of only uppercase and lowercase English letters. Uppercase and lowercase English letters are considered different. A sentence is circular if: The last character of each word in the sentence is equal to the first character of its next word. The last character of the last word is equal to the first character of the first word. For example, "leetcode exercises sound delightful", "eetcode", "leetcode eats soul" are all circular sentences. However, "Leetcode is cool", "happy Leetcode", "Leetcode" and "I like Leetcode" are not circular sentences. Given a string sentence, return true if it is circular. Otherwise, return false. Example 1: Input: sentence = "leetcode exercises sound delightful" Output: true Explanation: The words in sentence are ["leetcode", "exercises", "sound", "delightful"]. - leetcode's last character is equal to exercises's first character. - exercises's last character is equal to sound's first character. - sound's last character is equal to delightful's first character. - delightful's last character is equal to leetcode's first character. The sentence is circular. Example 2: Input: sentence = "eetcode" Output: true Explanation: The words in sentence are ["eetcode"]. - eetcode's last character is equal to eetcode's first character. The sentence is circular. Example 3: Input: sentence = "Leetcode is cool" Output: false Explanation: The words in sentence are ["Leetcode", "is", "cool"]. - Leetcode's last character is not equal to is's first character. The sentence is not circular. Constraints: 1 <= sentence.length <= 500 sentence consist of only lowercase and uppercase English letters and spaces. The words in sentence are separated by a single space. There are no leading or trailing spaces.

Explanation

Here's a breakdown of the solution:

• Split the sentence: The sentence is split into a list of words using the space character as a delimiter.
• Iterate and compare: Iterate through the list of words, comparing the last character of each word with the first character of the next word. For the last word, compare its last character with the first character of the first word.

• Return early if mismatch: If any mismatch is found during the comparison, return False immediately. Otherwise, if the loop completes without finding any mismatches, return True.

• Runtime Complexity: O(n), where n is the number of words in the sentence. Storage Complexity: O(n), where n is the number of words in the sentence, due to the words list.

Code

    def isCircularSentence(sentence: str) -> bool:
    """
    Checks if a sentence is circular.

    Args:
        sentence: The sentence to check.

    Returns:
        True if the sentence is circular, False otherwise.
    """
    words = sentence.split()
    n = len(words)

    for i in range(n):
        current_word = words[i]
        next_word = words[(i + 1) % n]  # Handle the circular case for the last word

        if current_word[-1] != next_word[0]:
            return False

    return True