Compilare: user.cpp: In function ‘void reset_viz()’: user.cpp:11:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<imp.size();++i) { ^ user.cpp: In function ‘void dfs(int)’: user.cpp:33:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<m[x].size();++i) { ^ user.cpp: In function ‘int trees(int)’: user.cpp:54:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<imp.size();++i) { ^ user.cpp: In function ‘int main()’: user.cpp:92:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zapezi2.in","r",stdin); ^ user.cpp:93:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zapezi2.out","w",stdout); ^ user.cpp:95:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&T); ^ user.cpp:97:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&N,&M); ^ user.cpp:100:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x[i],&y[i]); ^