Compilare: user.cpp: In function ‘void dfs1(int)’: user.cpp:12:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<g[k].size();i++) ^ user.cpp: In function ‘void dfs2(int)’: user.cpp:23:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<gt[k].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:65:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<c[i].size();j++) ^ user.cpp:33:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.in", "r", stdin); ^ user.cpp:34:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.out", "w", stdout); ^