exp:double=1e-8;
type
cover=record
l,r:double;
end;
var
i,j,k,m,n,w,h,x0,y0,ai:longint;
line:array[1..100000]of cover;
ans:longint;
r,rr:double;
procedure qsort(l,r:longint);
var
i,j:longint;
x:double;
tmp:cover;
begin
i:=l;j:=r;x:=line[(i+j)div 2].l;
repeat
while line[i].l<x do inc(i);
while line[j].l>x do dec(j);
if i<=j then
begin
tmp:=line[i];line[i]:=line[j];line[j]:=tmp;
inc(i);dec(j);
end;
until i>j;
if i<r then qsort(i,r);
if j>l then qsort(l,j);
end;
function max(a,b:double):double;
begin
if a>b then exit(a) else exit(b);
end;
begin
readln(w,h,n);
for i:=1 to n do
begin
readln(x0,y0,ai);
r:=(h-y0)*sin(ai*pi/360)/cos(ai*pi/360);
if x0-r<0 then line[i].l:=0 else line[i].l:=x0-r;
if x0+r>w then line[i].r:=w else line[i].r:=x0+r;
end;
qsort(1,n);
r:=0;ans:=0;
for i:=1 to n do
begin
rr:=r+exp;
j:=1;
while(j<=n)and(line[j].l<=rr)do
begin
r:=max(r,line[j].r);
inc(j);
end;
if r>rr then inc(ans)
else begin writeln(-1);exit;end;
if r>=w then break;
end;
writeln(ans);
end.
有空的看看吧，我觉得是正解了