Simple Python solution :

def marcsCakewalk(calorie):
    return sum(pow(2, i)*val for i,val in enumerate(sorted(calorie, reverse=True)))

Question's explnation is not clear.

public static long marcsCakewalk(List<Integer> calorie) {
    Comparator<Integer> comp = Integer::compare;
    List<Integer> cals = calorie.stream().sorted(comp.reversed()).collect(Collectors.toList());
    double mincal = 0;
    for(int i=0;i<cals.size();i++) {
        mincal +=  Math.pow(2, i)*cals.get(i);
    }        
    return (long)mincal;
}

c++ answer------- long marcsCakewalk(vector calorie) { sort(calorie.begin(),calorie.end(),greater()); long miles=0; for(int i=0;i

Here is my c++ solution, you can watch explanation here : https://youtu.be/RRJoL2vDmZM

long marcsCakewalk(vector<int> calorie) {
    sort(calorie.begin(), calorie.end(), [](int l, int r){return l > r;});
    long ans = 0;
    for(int i = 0; i < calorie.size(); i++){
        ans += pow(2, i) * calorie[i];
    }
    return ans;
}