Factoradic: предупреждения компилятора

[GassaFM]

@Gektor228, поправь эти предупреждения:

factoradic.cpp: In constructor 'Factoradic::Factoradic()':
factoradic.cpp:9:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 1; i <= MAX_FACT; i++) {
                       ^
factoradic.cpp: In member function 'virtual int64_t Factoradic::total(int)':
factoradic.cpp:19:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     return 0 <= n && n < MAX_FACT ? f[n + 1] : INT64_MAX;
                        ^
factoradic.cpp: In member function 'virtual std::vector<std::vector<int> > Factoradic::generate_all(int)':
factoradic.cpp:27:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 1; i < vec.size(); i++) {
                       ^
factoradic.cpp: In member function 'virtual bool Factoradic::is_valid(const std::vector<int>&)':
factoradic.cpp:37:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if (v[n - i - 1] < 0 || v[n - i - 1] > i + 1)
                                              ^
factoradic.cpp: In member function 'virtual int64_t Factoradic::number_by_object(const std::vector<int>&)':
factoradic.cpp:46:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 1; i <= m; i++) {
                       ^
factoradic.cpp: In member function 'virtual std::vector<int> Factoradic::object_by_number(int, int64_t)':
factoradic.cpp:60:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if (i <= MAX_FACT && k >= f[i]) {
               ^
factoradic.cpp: In member function 'virtual bool Factoradic::prev(std::vector<int>&)':
factoradic.cpp:84:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 1; i <= n; i++)
                           ^