NOI2004 小H的小屋

还是纯粹不会啊……到底该怎么办

http://blog.sina.com.cn/s/blog_86942b1401016m3g.html

http://www.cnblogs.com/datam-cy/archive/2012/06/12/NOI2004-hut.html

var n,m,i,ln,rn,lm,rm:longint;
    k1,k2,ans,tmp:double;
function area(s,len:longint;k:double):double;
 begin
 if s=0 then exit(0);
 area:=sqr(len div s)*k*(s-len mod s)+sqr(len div s+1)*k*(len mod s);
 end;
procedure main;
 begin
 readln(k1,k2,m,n);ans:=maxlongint;
 lm:=m-n mod m;rm:=n mod m;ln:=n div m;rn:=n div m+1;
 if rm=0 then ans:=(area(lm,100,k1)+area(lm*ln,100,k2))
 else
  for i:=lm*ln to 100-rm*rn do
   begin
   tmp:=area(lm,i,k1)+area(rm,100-i,k1)+area(lm*ln,i,k2)+area(rm*rn,100-i,k2);
   if tmp<ans then ans:=tmp;
   end;
 writeln(ans:0:1);
 end;
begin
 main;
end.