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ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#242313 | #7730. Convex Checker | invaded | WA | 1ms | 3580kb | C++17 | 4.6kb | 2023-11-07 09:51:38 | 2023-11-07 09:51:40 |
Judging History
你现在查看的是最新测评结果
- [2024-07-04 19:27:17]
- hack成功,自动添加数据
- (/hack/727)
- [2024-07-04 19:17:30]
- hack成功,自动添加数据
- (/hack/726)
- [2023-12-08 14:40:48]
- hack成功,自动添加数据
- (//qoj.ac/hack/493)
- [2023-11-07 10:32:52]
- hack成功,自动添加数据
- (//qoj.ac/hack/426)
- [2023-11-07 10:28:41]
- hack成功,自动添加数据
- (//qoj.ac/hack/425)
- [2023-11-07 09:51:38]
- 提交
answer
#include<bits/stdc++.h>
#ifndef xxx
#define dbg(...) ;
#endif
using namespace std;
//template<class T> ostream &operator<<(ostream &o, const vector <T> &v) { bool f=false; for(T i:v) { f?o<<' ':o; o<<(i); f=true; } return o; }
template<class T> void sort(T &v) { std::sort(v.begin(), v.end()); }
template<class T, class C> void sort(T &v, C c) { std::sort(v.begin(), v.end(), c); }
template<class T> void reverse(T &v) { std::reverse(v.begin(), v.end()); }
template<class T> bool is_sorted(T &v) { return std::is_sorted(v.begin(), v.end()); }
template<class T> inline void _min(T &x, const T &y) { x>y?x=y:x; }
template<class T> inline void _max(T &x, const T &y) { x<y?x=y:x; }
istream &operator>>(istream &i, __int128_t &x) { x=0; short f=1; char c=0; while(!isdigit(c)) { if(c=='-')f=-1; c=i.get(); } while(isdigit(c))x=x*10+c-'0', c=i.get(); x*=f; return i; }
ostream &operator<<(ostream &o, __int128_t x) { if(x==0) { o<<0; return o; } bool f=false; string s; if(x<0)f=true, x=-x; while(x)s+=x%10+'0', x/=10; reverse(s); if(f)o<<'-'; o<<s; return o; }
mt19937 mt(time(0));
typedef double db;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
constexpr int maxn=2e5+5;
constexpr int mod=1e9+7;
constexpr int inf=0x3f3f3f3f;
constexpr ll INF=0x3f3f3f3f3f3f3f3fll;
constexpr double pi=acos(-1.0);
constexpr double eps=1e-9;
struct Point
{
ll x, y;
void read()
{
cin>>x>>y;
}
bool operator<(const Point &p)const
{
return x==p.x?y<p.y:x<p.x;
}
bool operator==(const Point &p)const
{
return x==p.x&&y==p.y;
}
friend ostream &operator<<(ostream &o, const Point &p)
{
o<<'('<<p.x<<','<<p.y<<')';
return o;
}
};
struct Vect
{
ll x, y;
Vect() :x(0), y(0) {}
Vect(Point st, Point ed) :x(ed.x-st.x), y(ed.y-st.y) {}
ll dot(Vect V)
{
return x*V.x+y*V.y;
}
ll cross(Vect V)
{
return x*V.y-y*V.x;
}
ll toLeft(Vect V)
{
ll t=cross(V);
return (t>0)-(t<0);
}
};
Vect operator-(Point ed, Point st)
{
return Vect(st, ed);
}
vector<Point> convexHull1(vector<Point> p)
{
vector<Point> st;
if(p.empty()) return st;
sort(p.begin(), p.end());
const auto check=[](const vector<Point> &st, const Point &u)
{
const auto back1=st.back(), back2=*prev(st.end(), 2);
return (back1-back2).toLeft(u-back1)<=0;
};
for(const Point &u:p)
{
while(st.size()>1&&check(st, u)) st.pop_back();
st.push_back(u);
}
size_t k=st.size();
p.pop_back();
reverse(p.begin(), p.end());
for(const Point &u:p)
{
while(st.size()>k&&check(st, u)) st.pop_back();
st.push_back(u);
}
st.pop_back();
return st;
}
vector<Point> convexHull2(vector<Point> p)
{
vector<Point> st;
if(p.empty()) return st;
sort(p.begin(), p.end());
reverse(p);
const auto check=[](const vector<Point> &st, const Point &u)
{
const auto back1=st.back(), back2=*prev(st.end(), 2);
return (back1-back2).toLeft(u-back1)<=0;
};
for(const Point &u:p)
{
while(st.size()>1&&check(st, u)) st.pop_back();
st.push_back(u);
}
size_t k=st.size();
p.pop_back();
reverse(p.begin(), p.end());
for(const Point &u:p)
{
while(st.size()>k&&check(st, u)) st.pop_back();
st.push_back(u);
}
st.pop_back();
return st;
}
bool preCheck(const vector<Point> &poly)
{
int n=poly.size();
for(int i=0; i<n; i++)
{
int u=i;
int v=(i+1)%n;
int w=(i+2)%n;
Vect v1(poly[u], poly[v]);
Vect v2(poly[v], poly[w]);
if(v1.toLeft(v2)==0)
{
return false;
}
}
return true;
}
bool compare(const vector<Point> &poly, const vector<Point> &convex)
{
if(poly.size()!=convex.size())return false;
int n=poly.size();
int it=find(poly.begin(), poly.end(), convex.front())-poly.begin();
if(it==poly.size())return false;
auto check1=[&]()->bool
{
for(int i=(it+1)%n, j=1%n; i!=it; i=(i+1)%n, j=(j+1)%n)
{
if(poly[i]==convex[j])
{
continue;
}
else
{
return false;
}
}
};
auto check2=[&]()->bool
{
for(int i=(it-1+n)%n, j=n-1; i!=it; i=(i-1+n)%n, j=(j-1+n)%n)
{
if(poly[i]==convex[j])
{
continue;
}
else
{
return false;
}
}
};
return true;
}
int main()//MARK: main
{
#ifndef xxx
ios::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
#endif
cout<<fixed<<setprecision(10);
int n;
cin>>n;
vector<Point>poly(n);
for(int i=1; i<=n; i++)
{
poly[i-1].read();
}
auto convex1=convexHull1(poly);
auto convex2=convexHull2(poly);
//dbg(convex1);
//dbg(convex2);
bool flag=preCheck(poly)&&(compare(poly, convex1)||compare(poly, convex2));
cout<<(flag?"Yes":"No")<<'\n';
return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 0ms
memory: 3548kb
input:
3 0 0 1 0 0 1
output:
Yes
result:
ok answer is YES
Test #2:
score: 0
Accepted
time: 1ms
memory: 3580kb
input:
4 0 0 0 1 1 1 1 0
output:
Yes
result:
ok answer is YES
Test #3:
score: 0
Accepted
time: 0ms
memory: 3532kb
input:
4 0 0 0 3 1 2 1 1
output:
Yes
result:
ok answer is YES
Test #4:
score: 0
Accepted
time: 0ms
memory: 3552kb
input:
3 0 0 0 0 0 0
output:
No
result:
ok answer is NO
Test #5:
score: -100
Wrong Answer
time: 0ms
memory: 3532kb
input:
5 1 0 4 1 0 1 2 0 3 2
output:
Yes
result:
wrong answer expected NO, found YES