//Decode ways
//runtime on case 223/258
class Solution {
public:
    void backtrack(string s, int& count, int pos){
        if(pos>= s.size()){
            count++;
            return;
        }
        if(s[pos]== '0')
            return;
        backtrack(s,count, pos+1);
        //check if 2 digits is okay bs vslid l awl wla la2a
        if(pos < s.size()-1 && (((s[pos]-'0')*10)+(s[pos+1]-'0'))  <= 26 )
            backtrack(s,count, pos+2);

    }
    int numDecodings(string s) {
        int count=0;
        backtrack(s,count, 0);
        return count;
    }
};