61 lines
1.7 KiB
ObjectPascal
61 lines
1.7 KiB
ObjectPascal
var
|
||
n,ks,js:longint;
|
||
k:array[1..200] of longint; //每层数字ki
|
||
pd:array[1..200] of boolean; //判断该楼层到过了没有
|
||
i,j:longint;
|
||
t,w,l:longint;
|
||
q:array[1..10000,1..2] of longint; //把可能到过楼层的入队
|
||
|
||
procedure print(t:longint);
|
||
var
|
||
i,j:longint;
|
||
begin
|
||
if q[t,2]<>0 then print(q[t,2]);
|
||
inc(l);
|
||
end;
|
||
|
||
begin
|
||
assign(input,'lift.in'); reset(input);
|
||
assign(output,'lift.out');rewrite(output);
|
||
readln(n,ks,js);
|
||
for i:=1 to n do
|
||
read(k[i]);
|
||
fillchar(pd,sizeof(pd),true);
|
||
pd[ks]:=false;
|
||
q[1,1]:=ks;
|
||
t:=1; //队头指针
|
||
w:=1; //队尾指针
|
||
repeat
|
||
if q[t,1]=js then
|
||
begin
|
||
print(t);
|
||
writeln(l-1);
|
||
close(input);
|
||
close(output);
|
||
halt;
|
||
end;
|
||
if k[q[t,1]]<>0 then //若ki=0，则电梯就不动。
|
||
begin
|
||
if q[t,1]+k[q[t,1]]<=n then //电梯向上不能超过顶楼
|
||
if pd[q[t,1]+k[q[t,1]]] then //该楼层没到过
|
||
begin
|
||
inc(w); //入队
|
||
q[w,1]:=q[t,1]+k[q[t,1]];
|
||
q[w,2]:=t; //记下队头指针
|
||
pd[q[w,1]]:=false; //标记该楼层到过
|
||
end;
|
||
if q[t,1]-k[q[t,1]]>=1 then //电梯向下不能超过一楼
|
||
if pd[q[t,1]-k[q[t,1]]] then //该楼层没到过
|
||
begin
|
||
inc(w); //入队
|
||
q[w,1]:=q[t,1]-k[q[t,1]];
|
||
q[w,2]:=t; //记下队头指针
|
||
pd[q[w,1]]:=false; //标记该楼层到过
|
||
end;
|
||
end;
|
||
inc(t); //出队
|
||
until t>w;
|
||
writeln('-1');
|
||
close(input);
|
||
close(output);
|
||
end. |