#include <bits/stdc++.h>
using namespace std;
#define ios ios::sync_with_stdio(false); cin.tie(NULL);
#define pb push_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define fr first
#define sc second
#define mp make_pair
#define ll long long
#define double long double
const ll INF=1e18,N=1e6+5;
bool cmp(pair<double,double> a, pair<double,double> b){
if(a.sc==b.sc) return a.fr<b.fr;
return a.sc<b.sc;
}
int x[N],y[N];
double slope(int a, int b){
return (y[b]-y[a])/(x[b]-x[a]+0.0);
}
int cross(int A, int B, int C){
pair<int,int> a=mp(x[A],y[A]);
pair<int,int> b=mp(x[B],y[B]);
pair<int,int> c=mp(x[C],y[C]);
int tmp=a.fr*(b.sc-c.sc)+b.fr*(c.sc-a.sc)+c.fr*(a.sc-b.sc);
if(tmp>0) return 0;
if(tmp<0) return 1;
return 2;
}
vector< pair<double,double> > v;
deque<int> st;
int n,h;
void add(int i, int x){
while(st.size()>1 && cross(st[st.size()-2],st.back(),i)!=x)
st.pop_back();
st.pb(i);
}
double get(int i, int d){
while(st.size()>1 && cross(st[st.size()-2],st.back(),i)!=d)
st.pop_back();
int X=x[st.back()],Y=y[st.back()];
return (h-y[i])*1.0*(X-x[i])/(Y-y[i])+x[i];
}
void solve(){
cin>>n>>h;
for(int i=0;i<n;i++)
cin>>x[i]>>y[i];
vector<double> l(n),r(n);
for(int i=n-2;i>=3;i-=2){
add(i,0);
l[i-1]=get(i-1,0);
}
while(!st.empty()) st.pop_back();
for(int i=1;i<n-2;i+=2){
add(i,1);
r[i+1]=get(i+1,1);
}
for(int i=2;i<n-1;i+=2) v.pb(mp(l[i],r[i]));
sort(all(v));
int ans=0;
double rx=-INF;
for(int i=0;i<v.size();i++){
if(v[i].sc>rx+1e-9){
ans++;
rx=v[i].fr;
}
}
//cout<<fixed<<setprecision(3);
//for(auto it: v)
// cout<<it.fr<<' '<<it.sc<<endl;
cout<<ans;
}
int main(){
solve();
}
Compilation message
Main.cpp: In function 'void solve()':
Main.cpp:64:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long double, long double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
64 | for(int i=0;i<v.size();i++){
| ~^~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
7 ms |
3160 KB |
Output is correct |
2 |
Incorrect |
6 ms |
3164 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2 ms |
2396 KB |
Output is correct |
2 |
Correct |
2 ms |
2652 KB |
Output is correct |
3 |
Correct |
1 ms |
2396 KB |
Output is correct |
4 |
Correct |
2 ms |
2396 KB |
Output is correct |
5 |
Correct |
1 ms |
2392 KB |
Output is correct |
6 |
Incorrect |
2 ms |
2652 KB |
Output isn't correct |
7 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
7 ms |
3160 KB |
Output is correct |
2 |
Incorrect |
6 ms |
3164 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |