Problem Description
Given a sentence (a string consisting of words separated by a single space with no extra spaces), determine whether the sentence is circular. A sentence is circular if for every pair of consecutive words the last character of the current word equals the first character of the next word, and additionally, the last character of the last word equals the first character of the first word.
Key Insights
- Split the sentence into individual words using the space delimiter.
- Iterate through the word list and compare the last character of the current word with the first character of the next word.
- Use modulus arithmetic to compare the last word's last character with the first word's first character.
- The solution iterates through each word only once, leading to an efficient approach.
Space and Time Complexity
Time Complexity: O(n) where n is the number of characters in the sentence. Space Complexity: O(m) where m is the number of words in the sentence (storing the split list).
Solution
The solution splits the sentence into an array (or list) of words. It then iterates through the words, comparing the last character of each word with the first character of the next word. The circular condition is checked by using a wrap-around (modulus) for the comparison between the last word and the first word. This approach leverages simple string manipulation and modular arithmetic to ensure all conditions of a circular sentence are met.