3754. Concatenate Non-Zero Digits and Multiply by Sum I

You are given an integer n.

Form a new integer x by concatenating all the non-zero digits of n in their original order. If there are no non-zero digits, x = 0.

Let sum be the sum of digits in x.

Return an integer representing the value of x * sum.

class Solution {
public:
    long long sumAndMultiply(int n) {
        long long sum = 0, concat = 0;
        for(auto& ch : to_string(n)) {
            int x = ch - '0';
            if(x) {
                sum += x, concat = concat * 10 + x;
            }
        }
        return sum * concat;
    }
};