1876-substrings-of-size-three-with-distinct-characters.cpp

class Solution {
public:
    int countGoodSubstrings(string s) {
        if(s.size()<3)return 0;
        char a=s[0],b=s[1],c=s[2];
        int res=0;
        for(int i=3;i<=s.size()-1;i++)
        {
            if(a!=b and b!=c and c!=a)res++;
            a=b;
            b=c;
            c=s[i];
        }
        if(a!=b and b!=c and c!=a)res++;
        return res;
    }
};