Compilare: user.cpp: In function ‘void solve()’: user.cpp:106:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (st < mp[i - 1].size() && ivs[mp[i - 1][st]].y < ivs[j].x) ++st; ^ user.cpp:107:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (dr < mp[i - 1].size() && ivs[mp[i - 1][dr]].x <= ivs[j].y) ++dr; ^ user.cpp: In member function ‘char Reader::nextch()’: user.cpp:19:26: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, B, fin); ^