比赛 |
NOIP2008集训模拟5 |
评测结果 |
WWWTTTTTTA |
题目名称 |
数星星 |
最终得分 |
10 |
用户昵称 |
bing |
运行时间 |
0.000 s |
代码语言 |
Pascal |
内存使用 |
0.00 MiB |
提交时间 |
2008-11-14 11:17:21 |
显示代码纯文本
program bing;
var
f1,f2:text;
n,max:integer;
x,y:array[1..1000] of integer;
a:array[1..1000,1..1000] of integer;
b:array[1..1000,1..1000] of real;
procedure init;
var
i,j:integer;
begin
assign(f1,'stars.in');reset(f1);
assign(F2,'stars.out');rewrite(F2);
readln(f1,n);
for i:=1 to n do
readln(f1,x[i],y[i]);
fillchar(a,sizeof(a),0);
for i:=1 to n do
for j:=1 to n do b[i,j]:=0;
end;
procedure nb;
var
i,j,k:integer;
f:boolean;
t:real;
begin
for i:=1 to n do
begin a[1,i]:=1;b[1,i]:=1001;end;
for i:=1 to n-1 do
begin
a[2,i]:=2;
if y[i]-y[i+1]<>0 then
b[2,i]:=(x[i]-x[i+1])/(y[i]-y[i+1])
else b[2,i]:=1002;
end;
for i:=3 to n do
begin
for j:=1 to n-i+1 do
begin
for k:=1 to i-1 do
begin
f:=false;
if (k=1)or(i-k=1) then begin
if y[j]-y[j+k]<>0 then
t:=(x[j]-x[j+k])/(y[j]-y[j+k])
else t:=1002;
if (k=1)then if (t=b[i-k,j+k]) then f:=true;
if (i-k=1) then if (t=b[k,j]) then f:=true;
end
else if b[k,j]=b[i-k,j+k] then f:=true;
if f then
if (a[k,j]+a[i-k,j+k]>a[i,j]) then
begin
a[i,j]:=a[k,j]+a[i-k,j+k];
if b[k,j]<>1001 then b[i,j]:=b[k,j]
else b[i,j]:=b[i-k,j+k];
end;
end;
if a[i,j]>max then max:=a[i,j];
end;
end;
end;
begin
init;
nb;
write(f2,max);
close(F1);close(f2);
end.