【NOIP2017练习】函数变换（DP，dfs）

题意：

思路：

极限步数大概不会超过30

 const max=;
 var dp:array[..max,..]of longint;
     eul:array[..max]of longint;
     cas,v,n,k,i,ans,j:longint;

 function min(x,y:longint):longint;
 begin
  if x<y then exit(x);
  exit(y);
 end;

 function euler(x:longint):longint;
 var tmp,i:longint;
 begin
  if x<=max then exit(eul[x]);
  euler:=x; tmp:=trunc(sqrt(x));
  for i:= to tmp do
   if x mod i= then
   begin
    while x mod i= do x:=x div i;
    euler:=euler div i*(i-);
   end;
  if x> then euler:=euler div x*(x-);
 end;

 function clac(n,k:longint):longint;
 begin
  if n<=max then exit(dp[n,k]);
  clac:=clac(euler(n),k)+;
  if k> then clac:=min(clac,clac((n>>)+,k-)+);
 end;

 begin
  assign(input,'func.in'); reset(input);
  assign(output,'func.out'); rewrite(output);
  readln(cas);
  for i:= to max do eul[i]:=i;
  for i:= to max do
  begin
   if eul[i]=i then
    for j:= to max div i do eul[i*j]:=eul[i*j] div i*(i-);
   dp[i,]:=dp[eul[i],]+;
   dp[i,]:=min(dp[eul[i],],dp[(i>>)+,])+;
   dp[i,]:=min(dp[eul[i],],dp[(i>>)+,])+;
  end;

  for v:= to cas do
  begin
   readln(n,k);
   ans:=clac(n,);
   if k> then ans:=min(ans,clac(n,));
   if k> then ans:=min(ans,clac(n,));
   writeln(ans);
  end;
  close(input);
  close(output);
 end.