帮忙解一道pascal题目,有程序的

献上一个简单的dfs..
uses math;
var i,j,k,n:longint;
m,d:real;
map:array[0..110,0..110]of real;
x,y:array[0..110]of real;
dis:array[0..110]of real;
procedure dfs(p:integer;d:real);
var i:longint;
begin
dis[p]:=d;
for i:=1 to n do
if(map[p,i]>0)and((dis[i]=0)or(dis[i]>dis[p]+map[p,i]))then
dfs(i,dis[p]+map[p,i]);
end;
begin
readln(n,m);
for i:=1 to n do
readln(x[i],y[i]);
inc(n);
x[n]:=10;
y[n]:=10;
for i:=0 to n do begin
for j:=0 to n do begin
if(i=j)or(x[i]>=x[j])then
continue;
d:=sqrt((x[i]-x[j])**2+(y[i]-y[j])**2);
if(d<=m)then
map[i,j]:=d;
end;
end;
dfs(0,0);
writeln(dis[n]:0:2);
end.