记录编号	13170	评测结果	AAAAAAAAAA
题目名称	筷子	最终得分	100
用户昵称	maxiem	是否通过	通过
代码语言	Pascal	运行时间	0.005 s
提交时间	2009-09-29 12:09:58	内存使用	0.15 MiB

program chop;
var
  tmp,i,j,n,k:integer;
  c:array [1..100] of integer;
  dp:array [1..100,0..100] of longint;
begin
  for i:=0 to 100 do dp[1,i]:=0;
  for i:=2 to 100 do for j:=0 to 100 do dp[i,j]:=100000;
  assign (input,'chop.in');
  reset (input);
  readln (n,k);
  for i:=1 to n do read (c[i]);
  for i:=1 to n-1 do for j:=i+1 to n do if (c[i]>c[j]) then begin
    tmp:=c[i];
    c[i]:=c[j];
    c[j]:=tmp;
  end;
  close (input);
  assign (output,'chop.out');
  rewrite (output);
  if 2*k+6>n then writeln (-1) else begin
    dp[2,1]:=sqr(c[1]-c[2]);
    for i:=3 to n do for j:=1 to i div 2 do begin
      if dp[i-1,j]<dp[i-2,j-1]+sqr(c[i]-c[i-1]) then
        dp[i,j]:=dp[i-1,j]
      else
        dp[i,j]:=dp[i-2,j-1]+sqr(c[i]-c[i-1]);
    end;
    writeln (dp[n,k+3]);
  end;
  close (output);
end.