PASCAL基础爬楼梯

var
n,i,j,t,k1,k2:integer;
begin
fillchar(a,sizeof(a),0);
readln(n);
ifn=1then
t:=1;
ifn=2then
t:=2;
ifn>=3then
begin
k1:=1;
k2:=2;
fori:=3tondo
begin
j:=k1+k2;
k1:=k2;
k2:=j;
end;
t:=j;
end;
writeln(t);
end.
就是计算斐波那契数列

这道题是典型斐波拉契数列递推f[i]=f[i-1]+f[i-2]
var
f:array[1..30]oflongint;
i,n:longint;
begin
readln(n);
f[1]:=1;
f[2]:=1;
fori:=3tondo
f[i]:=f[i-1]+f[i-2];
writeln(f[n]);
end.

var
a:array[1..30]oflongint;
i,n:longint;
begin
readln(n);
a[1]:=1;a[2]:=2;
fori:=3tondoa[i]:=a[i-1]+a[i-2];
writeln(a[n]);
end.