Compilare: user.cpp: In function ‘void dijkstra(int)’: user.cpp:31:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<m[x].size(); ++i) { ^ user.cpp: In function ‘int main()’: user.cpp:65:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<e.size();++j) { ^ user.cpp:52:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dbz.in","r",stdin); ^ user.cpp:53:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("dbz.out","w",stdout); ^ user.cpp:55:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&N,&M); ^ user.cpp:57:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&x,&y,&z); ^