Compilare: user.cpp: In function ‘void kruskal()’: user.cpp:41:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(rs.size() < n-1){ ^ user.cpp: In function ‘int main()’: user.cpp:18:32: 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:19:34: 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: In function ‘void read()’: user.cpp:26:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d ",&n,&m); ^ user.cpp:29:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d ",&x,&y,&z); ^