Compilare: user.cpp: In function ‘bool SecondSquare(int, int, int, int, int, std::vector<std::pair<int, int> >)’: user.cpp:27:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < V.size(); ++ j) ^ user.cpp: In function ‘bool Can(int, int, int, int, int, std::vector<std::pair<int, int> >)’: user.cpp:53:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < V.size(); ++ j) ^ user.cpp: In function ‘int main()’: user.cpp:71:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("patrate.in", "r", stdin); ^ user.cpp:72:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("patrate.out", "w", stdout); ^ user.cpp:75:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i", &N); ^ user.cpp:78:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i", &X, &Y); ^