Substrings of Size Three with Distinct Characters

问长度为3的substring, 是不是都是不同字符的

class Solution {
    public int countGoodSubstrings(String s) {
        int n = s.length();
        if(n < 3)
            return 0; 
        int count = 0;
        for(int i = 0; i < n - 2; i++)
        {
            if(s.charAt(i) != s.charAt(i + 1) && s.charAt(i) != s.charAt(i + 2) && s.charAt(i + 1) != s.charAt(i + 2))
                count ++;
        }
        return count;
            
    }
}