Compilare: user.cpp: In function ‘void dfs(si)’: user.cpp:12:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(si i=0;i<G[x].size();i++){ ^ user.cpp: In function ‘void solve(si)’: user.cpp:23:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(si i=0;i<G[x].size();i++){ ^ user.cpp: In function ‘int main()’: user.cpp:31:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cezar.in","r",stdin); ^ user.cpp:32:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cezar.out","w",stdout); ^ user.cpp:34:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%hd%hd",&n,&k); ^ user.cpp:36:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%hd%hd",&a,&b); ^