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QOJ
ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#454900 | #7730. Convex Checker | Nephrenn | WA | 34ms | 8872kb | C++20 | 5.2kb | 2024-06-25 16:28:36 | 2024-06-25 16:28:38 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> PII;
typedef pair<ll, ll> PLL;
const int MAXN = 1e2 + 10;
const int INF = 0x3f3f3f3f;
const ll INFLL = 0x3f3f3f3f3f3f3f3f;
random_device seed;
mt19937 rnd(seed());
mt19937_64 rnd_64(seed());
const double eps = 1e-8;
int sgn(const double &x) {
return x < -eps ? -1 : (x > eps ? 1 : 0);
}
double sqr(const double &x) {
return x * x;
}
struct Point {
double x, y;
Point operator * (const double &k) {
return {x * k, y * k};
}
Point operator / (const double &k) {
return {x / k, y / k};
}
Point operator + (const Point &a) {
return {x + a.x, y + a.y};
}
Point operator - (const Point &a) {
return {x - a.x, y - a.y};
}
bool operator < (const Point &a) {
// return y == a.y ? x < a.x : y < a.y;
return x == a.x ? y < a.y : x < a.x;
}
double len() {
return sqrt(x * x + y * y);
}
};
istream &operator >> (istream &is, Point &p) {
is >> p.x >> p.y;
return is;
}
bool operator < (const Point &a, const Point &b) {
return a.x == b.x ? a.y < b.y : a.x < b.x;
}
bool operator == (const Point &a, const Point &b) {
return a.x == b.x && a.y == b.y;
}
double dis(const Point &a, const Point &b) {
return sqrt(sqr(a.x - b.x) + sqr(a.y - b.y));
}
double det(const Point &a, const Point &b) {
return a.x * b.y - b.x * a.y;
}
double det(const Point &a, const Point &b, const Point &c) {
return (a.x - b.x) * (c.y - b.y) - (a.y - b.y) * (c.x - b.x);
}
double dot(const Point &a, const Point &b) {
return a.x * b.x + a.y * b.y;
}
double dot(const Point &a, const Point &b, const Point &c) {
return (a.x - b.x) * (c.x - b.x) + (a.y - b.y) * (c.y - b.y);
}
struct Line {
Point s, t;
};
bool point_on_segment(Point &a, Line &l) {
return sgn(det(l.s - a, a - l.t)) == 0 && sgn(dot(l.s - a, a - l.t)) >= 0;
}
bool two_side(Point &a, Point &b, Line &c) {
return sgn(det(a - c.s, c.t - c.s)) * sgn(det(b - c.s, c.t - c.s)) < 0;
}
bool inter_judge(Line &a, Line &b) {
if(point_on_segment(b.s, a) || point_on_segment(b.t, a) || point_on_segment(a.s, b) || point_on_segment(a.t, b)) {
return true;
}
return two_side(a.s, a.t, b) && two_side(b.s, b.t, a);
}
Point line_intersect(Line &a, Line &b) {
double u = det(a.t - a.s, b.s - a.s);
double v = -det(a.t - a.s, b.t - a.s);
return (b.s * v + b.t * u) / (v + u);
}
double point_to_line(Point &p, Line &l) {
return abs(det(l.t - l.s, p - l.s)) / dis(l.s, l.t);
}
double point_to_segment(Point &p, Line &l) {
if(sgn(dot(l.s - p, l.t - l.s)) * sgn(dot(l.t - p, l.t - l.s)) <= 0) {
return point_to_line(p, l);
}
return min(dis(p, l.s), dis(p, l.t));
}
double area(vector<Point> &a) {
double res = 0;
for(int i = 0; i < a.size(); ++i) {
int j = (i + 1) % a.size();
res += det(a[i], a[j]);
}
return res / 2.0;
}
bool turn_left(Point &a, Point &b, Point &c) {
return sgn(det(b - a, c - a)) > 0;
}
bool same_dir(Line &a, Line &b) {
return sgn(det(b.t - b.s, a.t - a.s)) == 0 && sgn(dot(b.t - b.s, a.t - a.s)) > 0;
}
vector<Point> convex_hull_Graham(vector<Point> a) {
if(a.size() <= 2) return {}; // 或 return a;
Point base = *min_element(a.begin(), a.end());
sort(a.begin(), a.end(), [&](auto u, auto v) {
int s = sgn(det(u - base, v - base));
if(s) return s > 0;
else return sgn(dis(u, base) - dis(v, base)) < 0;
});
vector<Point> res;
for(auto i : a) {
while(res.size() > 1 && !turn_left(res[res.size() - 2], res[res.size() - 1], i)) {
res.pop_back();
}
res.push_back(i);
}
return res;
}
vector<Point> convex_hull_Andrew(vector<Point> a) {
if(a.size() <= 2) return {}; // 或 return a
sort(a.begin(), a.end());
vector<Point> res;
for(int i = 0; i < a.size(); ++i) {
while(res.size() > 1 && !turn_left(res[res.size() - 2], res[res.size() - 1], a[i])) {
res.pop_back();
}
res.push_back(a[i]);
}
int fix = res.size();
for(int i = a.size() - 2; i >= 0; --i) {
while(res.size() > fix && !turn_left(res[res.size() - 2], res[res.size() - 1], a[i])) {
res.pop_back();
}
res.push_back(a[i]);
}
res.pop_back();
return res;
}
void solve () {
int n;
cin >> n;
vector<Point> p(n);
for(int i = 0; i < n; ++i) cin >> p[i];
p.push_back(p[0]);
p.push_back(p[1]);
double sum = 0;
for(int i = 0; i < n; ++i) {
int j = i + 1, k = i + 2;
Point v1 = p[j] - p[i], v2 = p[k] - p[j];
if(sgn(det(v1, v2)) == 0) {
cout << "No\n";
return;
}
sum += acos(dot(v1, v2) / v1.len() / v2.len());
}
if(sgn(sum - 2 * acos(-1)) != 0) cout << "No\n";
else cout << "Yes\n";
}
int main () {
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int Task = 1;
// cin >> Task;
while (Task--) {
solve();
}
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 0ms
memory: 4140kb
input:
3 0 0 1 0 0 1
output:
Yes
result:
ok answer is YES
Test #2:
score: 0
Accepted
time: 0ms
memory: 4148kb
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: 4136kb
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: 3876kb
input:
3 0 0 0 0 0 0
output:
No
result:
ok answer is NO
Test #5:
score: 0
Accepted
time: 0ms
memory: 4020kb
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: 4144kb
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: 3920kb
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: 4208kb
input:
5 0 0 999999999 0 1000000000 50000000 999999999 1000000000 0 1000000000
output:
Yes
result:
ok answer is YES
Test #9:
score: 0
Accepted
time: 31ms
memory: 8872kb
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:
Yes
result:
ok answer is YES
Test #10:
score: -100
Wrong Answer
time: 34ms
memory: 8224kb
input:
128086 149550602 509469827 149551059 509465022 149551336 509462107 149551964 509455497 149552572 509449094 149553350 509440895 149553656 509437667 149554161 509432339 149554254 509431357 149554545 509428284 149555017 509423299 149555366 509419611 149555842 509414580 149556382 509408867 149556564 509...
output:
No
result:
wrong answer expected YES, found NO