Compilare: main.cpp:1:0: warning: ignoring #pragma gcc optimize [-Wunknown-pragmas] #pragma gcc optimize("O3") main.cpp: In function 'int solve(int)': main.cpp:95:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v[x].size(); ++i) ~~^~~~~~~~~~~~~ main.cpp: In member function 'char InParser::read_ch()': main.cpp:24:38: 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, 4096, fin); ^