>>648
// includeを追加(std::pair<>の使用のため)
#include <utility>
// ostream& operator<<(ostream&, const Mvalue&)を削除
// main()のfor文を次のように変更
    for (MMAP::iterator i = seisekiMap.begin(), end = seisekiMap.end(); i != end; ) {
        pair<MMAP::iterator, MMAP::iterator> p = seisekiMap.equal_range(i->first);
        cout << i->first << ":";
        for (MMAP::iterator first = p.first, last = p.second; first != last; ++first)
            cout << first->second << ' ';
        cout << endl;
        i = p.second;
    }