Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:35:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<g[nod].size();i++) dfs(g[nod][i]); ~^~~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:41:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("undo.in","r",stdin); ^ user.cpp:42:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("undo.out","w",stdout); ^ user.cpp:44:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:48:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&v[i].tip,&v[i].x); ^ user.cpp:49:54: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] if(v[i].tip==1) scanf("%d%d",&v[i].y,&v[i].z); ^ user.cpp:50:50: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] else if(v[i].tip==2) {scanf("%d",&v[i].y);v[i].z=++l;} ^