Сортировка Шейкером

Program ShakerSort; 
Var A : array[1..1000] of integer; 
N,i,j,p : integer; 
Min, Max : integer; 
Begin 
randomize;
writeln('Razmer massiva');
readln(N);
for i:=1 to N do
A[i]:=random(50);
for i:=1 to n div 2 do begin 
if A[i]>A[i+1] then begin 
Min:=i+1; 
Max:=i; 
end else begin 
Min:=i; 
Max:=i+1; 
end; 
for j:=i+2 to n-i+1 do 
if A[j]>A[Max] then Max:=j else if A[j] < A[min] then 
Min:=j; 
P:=A[i]; 
A[i]:=A[min]; 
A[min]:=P; 
if max=i then max:=min; 
P:=A[N-i+1]; 
A[N-i+1]:=A[max]; 
A[max]:=P; 
end; 
for i:=1 to N do
write(A[i],' ');
End.