Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:12:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<g[x].size(); i++) ^ user.cpp: In function ‘void del(int)’: user.cpp:22:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0; i<g[x].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:30:36: warning: unused variable ‘nr’ [-Wunused-variable] int n, t, a, b, c, i, j, x, y, nr; ^ user.cpp:31:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbxyz.in","r",stdin); ^ user.cpp:32:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbxyz.out","w",stdout); ^ user.cpp:33:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&t); ^ user.cpp:36:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&n,&a,&b,&c); ^ user.cpp:43:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y); ^