Compilare: user.cpp: In function ‘void buildBest(const std::vector<int>&)’: user.cpp:77:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 1; i < v.size(); ++i, swap(lv, ln)) ^ user.cpp: In function ‘int main()’: user.cpp:19:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pipe.in", "r", stdin); ^ user.cpp:20:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pipe.out", "w", stdout); ^