bzoj1293: [SCOI2009]生日礼物

uses math;
var
a:array [0..1000006] of longint;
p,h,l:array [0..65] of longint;
n,m,i,j,k,ma,mi,ans:longint;
procedure kp(l,r:longint);
var i,j,m,t:longint;
begin
i:=l; j:=r; m:=a[(l+r) div 2];
while (i<=j) do begin
while (a[i]<m) and (i<=r) do inc(i);
while (a[j]>m) and (j>=l) do dec(j);
if (i<=j) then begin
t:=a[i]; a[i]:=a[j]; a[j]:=t;
inc(i); dec(j);
end; end;
if (l<j) then kp(l,j);
if (i<r) then kp(i,r);
end;
begin
read(n,m);
for i:=1 to m do begin
read(l[i]); h[i]:=h[i-1]+l[i-1];
for j:=h[i] to h[i]+l[i]-1 do read(a[j]);
end;
p:=h; p[m+1]:=n+1;
ma:=0; mi:=maxlongint;
for i:=1 to m do begin
if (a[h[i]]>ma) then ma:=a[h[i]];
if (a[h[i]]<mi) then mi:=a[h[i]];
end;
ans:=ma-mi;
for i:=1 to n-m do
begin
k:=0;
for j:=1 to m do
if (h[j]+1<>p[j+1]) then
if (k=0) or (a[h[j]]<a[h[k]]) or ((a[h[j]]=a[h[k]]) and (a[h[j]+1]<a[h[k]+1])) then k:=j;
inc(h[k]);
ma:=0; mi:=maxlongint;
for j:=1 to m do begin
if (a[h[j]]>ma) then ma:=a[h[j]];
if (a[h[j]]<mi) then mi:=a[h[j]];
end;
ans:=min(ans,ma-mi);
end;
write(ans);
end.