Compilare: user.cpp: In function ‘void djikstra(int)’: user.cpp:19:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<G[x].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:37:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("salvare.in","r",stdin); ^ user.cpp:38:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("salvare.out","w",stdout); ^ user.cpp:39:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&N,&K); ^ user.cpp:40:80: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(int i=1;i<N;++i)scanf("%d%d",&x,&y),G[x].push_back(y),G[y].push_back(x); ^