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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#313374 | #7730. Convex Checker | xiaoxing666 | WA | 20ms | 5120kb | C++17 | 2.2kb | 2024-01-24 18:25:32 | 2024-01-24 18:25:32 |
Judging History
answer
#include <bits/stdc++.h>
#define endl '\n'
using namespace std;
typedef long long db;
const long double EPS = 1e-13;
const long double PI = acos(-1);
inline int sign(long double a) { return a < -EPS ? -1 : a > EPS; }
inline int cmp(long double a, long double b){ return sign(a-b); }
struct P {
db x, y;
P() {}
P(db _x, db _y) : x(_x), y(_y) {}
P operator+(P p) { return {x + p.x, y + p.y}; }
P operator-(P p) { return {x - p.x, y - p.y}; }
P operator*(db d) { return {x * d, y * d}; }
P operator/(db d) { return {x / d, y / d}; }
bool operator<(P p) const {
int c = cmp(x, p.x);
if (c) return c == -1;
return cmp(y, p.y) == -1;
}
bool operator==(P o) const{
return cmp(x,o.x) == 0 && cmp(y,o.y) == 0;
}
db dot(P p) { return x * p.x + y * p.y; } //点乘
db det(P p) { return x * p.y - y * p.x; } //叉乘
db distTo(P p) { return (*this-p).abs(); }
double alpha() { return atan2(y, x); }
void read() { cin>>x>>y; }
void write() {cout<<"("<<x<<","<<y<<")"<<endl;}
db abs() { return sqrt(abs2());}
db abs2() { return x * x + y * y; }
P rot90() { return P(-y,x);} //旋转90度
P unit() { return *this/abs(); }
int quad() const { return sign(y) == 1 || (sign(y) == 0 && sign(x) >= 0); }
};
#define cross(p1,p2,p3) ((p2.x-p1.x)*(p3.y-p1.y)-(p3.x-p1.x)*(p2.y-p1.y))
#define crossOp(p1,p2,p3) sign(cross(p1,p2,p3)) //逆时针正,顺时针负,共线0
int n;
vector<P> p;
int main()
{
ios::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
cin >> n;
for(int i = 0; i < n; i++)
{
db x, y;
cin >> x >> y;
p.push_back({x, y});
}
int b = sign((p[0] - p[n - 1]).det(p[1] - p[0]));
if(b > 0)
{
reverse(p.begin(), p.end());
}
bool fl = 1;
double ans = 0;
for(int i = 0; i < n; i++)
{
P tmp1 = p[i] - p[(i - 1 + n) % n];
P tmp2 = p[(i + 1) % n] - p[i];
P tmp3 = p[(i - 1 + n) % n] - p[i];
if(sign(tmp2.det(tmp1)) <= 0)
{
fl = 0;
break;
}
if(p[i - 1] == p[i]){
fl = 0;
break;
}
ans += fabs(atan2(fabs(tmp2.det(tmp3)),tmp2.dot(tmp3)));
}
if(fl && cmp(ans, (n - 2) * PI) == 0)
cout << "Yes" << endl;
else
cout << "No" << endl;
return 0;
}
Details
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Test #1:
score: 100
Accepted
time: 0ms
memory: 3964kb
input:
3 0 0 1 0 0 1
output:
Yes
result:
ok answer is YES
Test #2:
score: 0
Accepted
time: 0ms
memory: 3720kb
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: 3964kb
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: 3616kb
input:
3 0 0 0 0 0 0
output:
No
result:
ok answer is NO
Test #5:
score: 0
Accepted
time: 0ms
memory: 3900kb
input:
5 1 0 4 1 0 1 2 0 3 2
output:
No
result:
ok answer is NO
Test #6:
score: 0
Accepted
time: 0ms
memory: 3716kb
input:
5 0 0 1000000000 0 1000000000 500000000 1000000000 1000000000 0 1000000000
output:
No
result:
ok answer is NO
Test #7:
score: 0
Accepted
time: 0ms
memory: 3648kb
input:
5 0 0 1000000000 0 1000000000 499999999 1000000000 1000000000 0 1000000000
output:
No
result:
ok answer is NO
Test #8:
score: 0
Accepted
time: 0ms
memory: 3972kb
input:
5 0 0 999999999 0 1000000000 50000000 999999999 1000000000 0 1000000000
output:
Yes
result:
ok answer is YES
Test #9:
score: -100
Wrong Answer
time: 20ms
memory: 5120kb
input:
128312 5578014 410408218 5585076 410404717 5588011 410403262 5588473 410403033 5589740 410402405 5593295 410400643 5593751 410400417 5597248 410398684 5598935 410397848 5600618 410397014 5605185 410394751 5610514 410392111 5614281 410390245 5617263 410388768 5621142 410386847 5630840 410382045 56310...
output:
No
result:
wrong answer expected YES, found NO