Pascal 取数描述 Description 给出长度为N的数列{A-i},每次可以从最左边或者最右边取走一个数,第i

就是一个很简单的dp题.
var
n,m,i,j,k,t,s,d:longint;
a:array[0..2001] of longint;
f:array[-2..2001,-2..2001] of longint;
function max(p,q:longint):longint;
begin
if p>q then
exit(p)
else
exit(q);
end;
begin
readln(n);
for i:=1 to n do
readln(a[i]);
fillchar(f,sizeof(f),0);
for i:=1 to n do
for j:=n downto i-1 do
f[i,j]:=max(f[i,j+1]+(i-1+n-j)*a[j+1],f[i-1,j]+(i-j+n-1)*a[i-1]);
for i:=1 to n do
if s