LeetCode-in-Java

2490. Circular Sentence

Easy

A sentence is a list of words that are separated by a single space with no leading or trailing spaces.

Words consist of only uppercase and lowercase English letters. Uppercase and lowercase English letters are considered different.

A sentence is circular if:

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”].

The sentence is circular.

Example 2:

Input: sentence = “eetcode”

Output: true

Explanation: The words in sentence are [“eetcode”].

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:

Solution

public class Solution {
    public boolean isCircularSentence(String sentence) {
        char[] letters = sentence.toCharArray();
        int len = letters.length;
        for (int i = 0; i < len - 1; ++i) {
            if (letters[i] == ' ' && letters[i - 1] != letters[i + 1]) {
                return false;
            }
        }
        return letters[0] == letters[len - 1];
    }
}