#include<cstdio>
#include<vector>
#include<algorithm>
using namespace std;
const double PI = acos(0.0)*2;
typedef pair<int, int> point;
#define X first
#define Y second
int n, r;
vector<point> points;
long long ccw(point a, point b, point c) {
b.first -= a.first; b.second -= a.second;
c.first -= a.first; c.second -= a.second;
return b.first * (long long)c.second - c.first * (long long)b.second;
}
vector<point> convexHull(vector<point> dat) {
vector<point> upper, lower;
sort(dat.begin(), dat.end());
for(int i = 0; i < dat.size(); i++) {
while(upper.size() >= 2 && ccw(*++upper.rbegin(),*upper.rbegin(),dat[i]) >= 0) upper.pop_back();
while(lower.size() >= 2 && ccw(*++lower.rbegin(),*lower.rbegin(),dat[i]) <= 0) lower.pop_back();
upper.emplace_back(dat[i]);
lower.emplace_back(dat[i]);
}
upper.insert(upper.end(), ++lower.begin(), --lower.end());
return upper;
}
double dist(point a, point b) {
return hypot(a.X-b.X, a.Y-b.Y);
}
int main() {
scanf("%d%d", &n, &r);
for (int i=0; i<n; ++i) {
int x, y;
scanf("%d%d", &x, &y);
points.emplace_back(x, y);
}
auto hull = convexHull(points);
double ans = dist(hull[0], hull[hull.size()-1]);
for (int i=1; i<hull.size(); ++i)
ans += dist(hull[i], hull[i-1]);
ans += 2*PI*r;
printf("%.15f\n", ans);
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
1256 KB |
Output is correct |
2 |
Correct |
0 ms |
1256 KB |
Output is correct |
3 |
Correct |
0 ms |
1256 KB |
Output is correct |
4 |
Correct |
0 ms |
1256 KB |
Output is correct |
5 |
Correct |
0 ms |
1256 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
0 ms |
1256 KB |
Output is correct |
2 |
Incorrect |
0 ms |
1256 KB |
Output isn't correct |
3 |
Halted |
0 ms |
0 KB |
- |