answer.code:5:82: error: redefinition of ‘int ret’
    5 | int n,k,hd[N],mn,f[N][K],g[N][K],a[N],sz[N],dfn[N],ans[N],rt,ret,vs[N],e_num,idx,ret;
      |                                                                                  ^~~
answer.code:5:62: note: ‘int ret’ previously declared here
    5 | int n,k,hd[N],mn,f[N][K],g[N][K],a[N],sz[N],dfn[N],ans[N],rt,ret,vs[N],e_num,idx,ret;
      |                                                              ^~~
answer.code: In function ‘int main()’:
answer.code:74:14: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   74 |         scanf("%d%d",&n,&k);
      |         ~~~~~^~~~~~~~~~~~~~
answer.code:76:22: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   76 |                 scanf("%d",a+i);
      |                 ~~~~~^~~~~~~~~~
answer.code:78:22: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   78 |                 scanf("%d%d",&u,&v),add_edge(u,v),add_edge(v,u);
      |                 ~~~~~^~~~~~~~~~~~~~