Compilare: user.cpp: In function ‘int main()’: user.cpp:57:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (ama.size() == N) { ^ user.cpp:63:45: warning: format ‘%lu’ expects argument of type ‘long unsigned int’, but argument 3 has type ‘std::vector<Edge>::size_type {aka unsigned int}’ [-Wformat=] printf("%d\n%lu\n", min_cost, ama.size()); ^ user.cpp:32:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("apm.in", "r", stdin); ^ user.cpp:33:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("apm.out", "w", stdout); ^ user.cpp:35:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ user.cpp:46:69: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d%d", &edges[i].n1, &edges[i].n2, &edges[i].cost); ^