Compilare: user.cpp: In function ‘void dijkstra(Point)’: user.cpp:30:17: warning: statement has no effect [-Wunused-value] vis[p.x][p.y]; ^ user.cpp:33:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<g[(dad.x-1)*m+dad.y].size();i++){ ^ user.cpp: In function ‘int main()’: user.cpp:50:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("taxa.in","r",stdin); ^ user.cpp:51:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("taxa.out","w",stdout); ^ user.cpp:52:56: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d%d%d",&n,&m,&st.x,&st.y,&fn.x,&fn.y); ^ user.cpp:55:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a[i][j]); ^