codevs1006

题目地址：http://codevs.cn/problem/1006/

分析：

  冒泡排序+暴力

代码：

var i,j,n,m,max,dx,k:longint;
a:array[0..101]of longint;

begin
read(n);
for i:=1 to n do
read(a[i]);

for i:=1 to n-1 do
for j:=i+1 to n do
if a[i]>a[j] then begin m:=a[i];a[i]:=a[j];a[j]:=m;end;

for i:=1 to n-1 do
for j:=i+1 to n do
begin
m:=0;
for k:=j to n do
begin
if m=0 then
dx:=a[i]-a[j];
if (a[i]-(m+1)*dx=a[k]) then inc(m);end;
if m>max then max:=m;
end;

write(max+1);
end.