sort-string.cc

#include <unordered_map>
#include <string>
#include <iostream>

void sorted(const std::string &a, const std::string &order) {
    std::unordered_map<char, unsigned int> count;
    for (auto c : a)
        ++count[c];
    for (auto c: order) {
        for (auto i = count[c]; i > 0; --i) 
            std::cout << c;
    }
    std::cout << std::endl;
}


int main() {
    sorted("hello", "loadeh");
}