记录编号	39469	评测结果	AAAAAAAAAAAA
题目名称	平衡奶牛	最终得分	100
用户昵称	zhangchi	是否通过	通过
代码语言	Pascal	运行时间	0.475 s
提交时间	2012-07-11 19:31:40	内存使用	92.48 MiB

type
  node=record
         postion,next:int64;
       end;
var
  i,j:longint;
  n,temp,k,ans,tot,t,pos:int64;
  q:boolean;
  a:array[1..100000] of int64;
  sum:array[1..30,0..100000] of int64;
  hash:array[0..3000008] of int64;
  link:array[1..3000000] of node;
begin
  assign(input,'balline.in'); reset(input);
  assign(output,'balline.out'); rewrite(output);
  readln(n,k);
  for i:=1 to n do
    readln(a[i]);
  for i:=1 to k do
    for j:=1 to n do
      sum[i,j]:=sum[i,j-1]+(a[j] shr (i-1)) and 1;
  for i:=1 to k-1 do
    for j:=1 to n do
      sum[i,j]:=sum[i,j]-sum[i+1,j];
  for i:=0 to n do
    begin
      temp:=1;
      for j:=1 to k-1 do
        temp:=(temp*13137+sum[j,i]) mod 1000007;
      t:=hash[temp];
      while t<>0 do
        begin
          pos:=link[t].postion;
          q:=true;
          for j:=1 to k-1 do
            if sum[j,i]<>sum[j,pos] then
              begin q:=false; break; end;
          if q=true then
            if i-pos>ans then ans:=i-pos;
          t:=link[t].next;
        end;
      inc(tot);
      link[tot].next:=hash[temp];
      hash[temp]:=tot;
      link[tot].postion:=i;
    end;
  writeln(ans);
  close(input); close(output);
end.