/*input
*/
#include<bits/stdc++.h>
using namespace std;
#define REP(i,n) for(int i=0;i<n;i++)
#define MNTO(x,y) x=min(x,y)
#define MXTO(x,y) x=max(x,y)
#define REP1(i,n) for(int i=1;i<=n;i++)
#define ll long long
#define ld long double
#define sz(x) (int)x.size()
#define pii pair<ll,ll>
#define pdd pair<ld,ld>
#define f first
#define s second
#define pb push_back
#define ALL(x) x.begin(),x.end()
const int INF=0x3f3f3f3f;
const int maxn=1e6+5;
ll triangle(pii o,pii a,pii b){
if(o.f==-1e6-1) return a.s<=b.s;
return (a.f-o.f)*(b.s-o.s)-(b.f-o.f)*(a.s-o.s);
}
bool cmp(pdd a,pdd b){
return a.s<b.s;
}
const ld eps=1e-9;
pii arr[maxn];
int main(){
ios::sync_with_stdio(false),cin.tie(0);
int n,h;
cin>>n>>h;
vector<pdd> vv;
REP(i,n) cin>>arr[i].f>>arr[i].s;
vector<pii> v;
v.pb({-1e6-1,h});
REP1(i,n-2){
while(sz(v)>=2 and triangle(v[sz(v)-2],v[sz(v)-1],arr[i])>0){
v.pop_back();
}
if(i%2==0){
vv.pb({0,0});
ld m=1.0*(v.back().s-arr[i].s)/(v.back().f-arr[i].f);
ld c=arr[i].s-m*arr[i].f;
vv[sz(vv)-1].f=(h-c)/m;
}
v.pb(arr[i]);
}
REP(i,n) arr[i].f*=-1;
v.clear();
v.pb({-1e6-1,h});
for(int i=n-2;i>=1;i--){
while(sz(v)>=2 and triangle(v[sz(v)-2],v[sz(v)-1],arr[i])>0){
v.pop_back();
}
if(i%2==0){
ld m=1.0*(v.back().s-arr[i].s)/(v.back().f-arr[i].f);
ld c=arr[i].s-m*arr[i].f;
ld z=(h-c)/m;
vv[i/2-1].s=-z;
}
v.pb(arr[i]);
}
sort(ALL(vv),cmp);
ld cur=vv[0].s;
int ans=1;
for(auto x:vv){
//cout<<x.s<<' '<<x.f<<'\n';
if(x.f>cur+eps) ++ans,cur=x.s;
}
cout<<ans;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
852 KB |
Output is correct |
2 |
Correct |
3 ms |
852 KB |
Output is correct |
3 |
Correct |
3 ms |
852 KB |
Output is correct |
4 |
Correct |
26 ms |
4052 KB |
Output is correct |
5 |
Correct |
30 ms |
4124 KB |
Output is correct |
6 |
Correct |
32 ms |
4052 KB |
Output is correct |
7 |
Correct |
263 ms |
32436 KB |
Output is correct |
8 |
Correct |
278 ms |
32444 KB |
Output is correct |
9 |
Correct |
307 ms |
32532 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
340 KB |
Output is correct |
2 |
Correct |
1 ms |
340 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
4 |
Correct |
1 ms |
340 KB |
Output is correct |
5 |
Correct |
0 ms |
212 KB |
Output is correct |
6 |
Correct |
1 ms |
340 KB |
Output is correct |
7 |
Correct |
1 ms |
212 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
4 ms |
852 KB |
Output is correct |
2 |
Correct |
3 ms |
852 KB |
Output is correct |
3 |
Correct |
3 ms |
852 KB |
Output is correct |
4 |
Correct |
26 ms |
4052 KB |
Output is correct |
5 |
Correct |
30 ms |
4124 KB |
Output is correct |
6 |
Correct |
32 ms |
4052 KB |
Output is correct |
7 |
Correct |
263 ms |
32436 KB |
Output is correct |
8 |
Correct |
278 ms |
32444 KB |
Output is correct |
9 |
Correct |
307 ms |
32532 KB |
Output is correct |
10 |
Correct |
1 ms |
340 KB |
Output is correct |
11 |
Correct |
1 ms |
340 KB |
Output is correct |
12 |
Correct |
0 ms |
212 KB |
Output is correct |
13 |
Correct |
1 ms |
340 KB |
Output is correct |
14 |
Correct |
0 ms |
212 KB |
Output is correct |
15 |
Correct |
1 ms |
340 KB |
Output is correct |
16 |
Correct |
1 ms |
212 KB |
Output is correct |
17 |
Correct |
302 ms |
32624 KB |
Output is correct |
18 |
Correct |
286 ms |
32772 KB |
Output is correct |
19 |
Correct |
34 ms |
4048 KB |
Output is correct |
20 |
Correct |
281 ms |
32516 KB |
Output is correct |
21 |
Correct |
30 ms |
4068 KB |
Output is correct |
22 |
Correct |
289 ms |
32804 KB |
Output is correct |
23 |
Correct |
0 ms |
212 KB |
Output is correct |
24 |
Correct |
283 ms |
32632 KB |
Output is correct |
25 |
Correct |
29 ms |
4048 KB |
Output is correct |
26 |
Correct |
364 ms |
32660 KB |
Output is correct |
27 |
Correct |
13 ms |
2252 KB |
Output is correct |