Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:27:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < G[k].size(); ++i){ ^ user.cpp: In function ‘int main()’: user.cpp:71:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < comp[i].size(); ++j){ ^ user.cpp:73:52: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = 0; k < Gr[comp[i][j]].size() && j + 1 < comp[i].size(); ++k){ ^ user.cpp:73:78: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = 0; k < Gr[comp[i][j]].size() && j + 1 < comp[i].size(); ++k){ ^ user.cpp:79:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(ok == 0 && j + 1 < comp[i].size()){ ^ user.cpp:43:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("biperm.in","r",stdin); ^ user.cpp:44:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("biperm.out","w",stdout); ^ user.cpp:45:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:47:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a[i]); ^ user.cpp:49:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&b[i]); ^