Compilare: main.cpp: In function 'long long int solve(int, int)': main.cpp:32:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(idx == factors.size()) ~~~~^~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:55:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < factors.size() ; ++i) ~~^~~~~~~~~~~~~~~~ main.cpp:63:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = last ; i < factors.size() ; ++i) ~~^~~~~~~~~~~~~~~~ main.cpp:46:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("desc.in" , "r" , stdin) ; ^ main.cpp:47:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("desc.out" , "w" , stdout) ; ^