Compilare: user.cpp: In function ‘void paranthesis_form(int, int)’: user.cpp:12:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<g[nod].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:55:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbnr.in","r",stdin); ^ user.cpp:56:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbnr.out","w",stdout); ^ user.cpp:58:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:60:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&dim[i]); ^ user.cpp:64:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&x); ^