Compilare: user.cpp: In function ‘void Initialization()’: user.cpp:33:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<cost[1].size();i++) ^ user.cpp: In function ‘void Prim()’: user.cpp:53:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<cost[y].size();i++) ^ user.cpp: In function ‘void Write()’: user.cpp:67:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<sol.size();i++) ^ user.cpp: In function ‘void Read()’: user.cpp:14:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&N,&M); ^ user.cpp:17:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&x,&y,&z); ^ user.cpp: In function ‘int main()’: user.cpp:73:32: 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:74:34: 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); ^