Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:40:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<p[x].size();i++) { ^ user.cpp: In function ‘int main()’: user.cpp:52:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,a,b,c,d; ^ user.cpp:49:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("import.in","r",stdin); ^ user.cpp:50:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("import.out","w",stdout); ^ user.cpp:51:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d",&n,&m,&k); ^ user.cpp:55:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&a,&b); ^ user.cpp:63:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d",&a,&b,&c,&d); ^