Сортировка map по значению

map<string, int> MyMap;

#include <iostream>
#include <string>
#include <map>
 
int main ()
{
  std::map< std::string,int> mymap;
 
  mymap["b"] = 100;
  mymap["a"] = 200;
  mymap["c"] = 300;
 
  // show content:
  for (std::map< std::string,int>::iterator it=mymap.begin(); it!=mymap.end(); ++it)
    std::cout << it->first << " => " << it->second << '\n';
 
  return 0;
}

    std::map<std::string, size_t> paths = {};
//....
    multimap<int, string> sortedPaths = {};
//....
    for(auto it = paths.rbegin(); it != paths.rend(); ++it)
    {
        int key = (*it).second;
        string val = (*it).first;
        sortedPaths.insert(std::pair<int, string>(key, val));
    }
 
//вывод
        for(auto it = sortedPaths.rbegin(); it != sortedPaths.rend(); ++it)
            cout << " " << (*it).first << " " << (*it).second << endl;

sort(v.begin(),v.end(),[](const pair<string,int> &a,const pair<string,int> &b){
          a.second<b.second;
});

#include <iostream>
#include <map>
#include <algorithm>
 
int main()
{
    std::map<std::string, int> m1;
    std::map<int, std::string> m2;
    
    std::transform(m1.begin(), m1.end(), std::inserter(m2, m2.end()), [] (const std::pair<const std::string, int> & p) { return std::make_pair(p.second, p.first); });
}