Compilare: user.cpp: In function ‘void dijkstra()’: user.cpp:29:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<a[j].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:39:27: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(inf,"r",stdin); ^ user.cpp:40:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(outf,"w",stdout); ^ user.cpp:43:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&m); ^ user.cpp:45:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d",&i,&j,&k); ^