Compilare: user.cpp: In function ‘void DFS(int)’: user.cpp:35:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < a[x].size() ;++i) ^ user.cpp:40:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < v[x].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:47:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("stramosi.in","r",stdin); ^ user.cpp:48:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("stramosi.out","w",stdout); ^ user.cpp:49:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:52:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x); ^ user.cpp:62:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&q[i].x,&q[i].y); ^