Compilare: main.cpp: In function 'std::vector<std::pair<int, long long int> > Merge(const std::vector<std::pair<int, long long int> >&, const std::vector<std::pair<int, long long int> >&)': main.cpp:37:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<a.size() && j<b.size()) ~^~~~~~~~~ main.cpp:37:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<a.size() && j<b.size()) ~^~~~~~~~~ main.cpp:56:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<a.size()) ~^~~~~~~~~ main.cpp:62:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j<b.size()) ~^~~~~~~~~ main.cpp: In function 'int main()': main.cpp:72:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("teste.in", "r", stdin); ^ main.cpp:73:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("teste.out", "w", stdout); ^