Compilare: main.cpp: In function 'int main()': main.cpp:30:32: warning: format '%i' expects argument of type 'int', but argument 2 has type 'std::set<std::pair<int, int> >::size_type {aka long unsigned int}' [-Wformat=] printf("%i\n", V.size()); ^ main.cpp:10:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sea2.in", "r", stdin); ^ main.cpp:11:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sea2.out", "w", stdout); ^ main.cpp:13:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%i", &n); ^ main.cpp:17:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i", &x, &y); ^