POJ 1328（贪心）

Program P1328;
var
n,d,i,j,k,ans:longint;
x:double;
tag:boolean;
map:array[1..1000,1..2] of double;
procedure qsort(l,r:longint);
var
i,j:longint;
m,p:double;
begin
i:=l;
j:=r;
m:=map[(l+r) div 2,1];
repeat
while map[i,1]<m do inc(i);
while map[j,1]>m do dec(j);
if i<=j then
begin
p:=map[i,1];
map[i,1]:=map[j,1];
map[j,1]:=p;
p:=map[i,2];
map[i,2]:=map[j,2];
map[j,2]:=p;
inc(i);
dec(j);
end;
until i>j;
if l<j then qsort(l,j);
if i<r then qsort(i,r);
end;
begin
i:=1;
{   assign(input,'P1328.in');
assign(output,'P1328.out');
reset(input);
rewrite(output);   }
while not seekeof do
begin
tag:=true;
read(n,d);
if d<=0 then tag:=false;
if (n=0) and (d=0) then break;
j:=1;
for k:=1 to n do
begin
read(map[j,1],map[j,2]);
if map[j,2]<0  then continue;
if d<map[j,2] then continue;
x:=sqrt(d*d-map[j,2]*map[j,2]);
map[j,2]:=map[j,1]+x;
map[j,1]:=map[j,1]-x;
inc(j);
end;
dec(j);
if tag and (j=n) then
begin
qsort(1,j);
ans:=1;
x:=map[1,2];
for k:=2 to j do
begin
if (map[k,2]<x) then
begin
x:=map[k,2];
end
else if (x<map[k,1]) then
begin
inc(ans);
x:=map[k,2];
end;

end;

writeln('Case ',i,': ',ans);
end
else writeln('Case ',i,': -1');
inc(i);
end;
{  close(input);
close(output);   }
end.