Compilare: user.cpp: In function ‘void DFS1(int)’: user.cpp:10:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<g[x].size(); ++i) ^ user.cpp: In function ‘void DFS2(int, bool)’: user.cpp:19:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<g2[x].size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:24:32: 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:25:34: 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); ^ user.cpp:26:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:29:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^