# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
367876 | ogibogi2004 | Triangles (CEOI18_tri) | C++14 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include<bits/stdc++.h>
using namespace std;
#define ll long long
ll n;
int t;
bool cmp1(int x,int y)
{
return is_clockwise(x,y,t);
}
bool cmp2(int x,int y)
{
return is_clockwise(x,t,y);
}
int main()
{
n=get_n();
vector<int>v1,v2;
for(int i=3;i<=n;i++)
{
if(is_clockwise(1,2,i))
{
v2.push_back(i);
}
else
{
v1.push_back(i);
}
}
t=2;
sort(v1.begin(),v1.begin(),cmp1);
v1.push_back(1);
reverse(v1.begin(),v1.end());
v1.push_back(2);
sort(v2.begin(),v2.begin(),cmp2);
deque<int>UH,LH;
UH.push_back(v1[0]);
for(int i=1;i<v1.size();i++)
{
while(UH.size()>=2&&!is_clockwise(UH.end()[-2],UH.end()[-1],v1[i]))
{
UH.pop_back();
}
UH.push_back(v1[i]);
}
if(v2.size()>0)
{
LH.push_back(v2[0]);
}
for(int i=1;i<v2.size();i++)
{
while(LH.size()>=2&&!is_clockwise(LH.end()[-2],LH.end()[-1],v2[i]))
{
LH.pop_back();
}
LH.push_back(v2[i]);
}
while(UH.size()>0&&LH.size()>0&&UH.size()+LH.size()>3)
{
if(UH.size()>1)
{
if(is_clockwise(UH[1],UH[0],LH[0]))
{
UH.pop_front();
continue;
}
if(!is_clockwise(UH.end()[-2],UH.end()[-1],LH.back()))
{
UH.pop_back();
continue;
}
}
if(LH.size()>1)
{
if(!is_clockwise(LH[1],LH[0],UH[0]))
{
LH.pop_front();
continue;
}
if(is_clockwise(LH.end()[-2],LH.end()[-1],UH.back()))
{
LH.pop_back();
continue;
}
}
break;
}
give_answer(UH.size()+LH.size());
return 0;
}
/*
6
1 1
5 1
3 2
2 2
4 3
1 4
*/