Compilare: main.cpp: In function 'void dfs(int)': main.cpp:11:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<ma[x].size(); ++i) ~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:18:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("easygraph.in","r",stdin); ^ main.cpp:19:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("easygraph.out","w",stdout); ^ main.cpp:21:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&t); ^ main.cpp:25:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ main.cpp:27:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] {scanf("%d",&v[i]); ^ main.cpp:31:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^