uva 2453 凸包

来源：互联网发布：mp3剪切合并大师 mac 编辑：程序博客网时间：2024/06/09 15:47
#include <bits/stdc++.h>using namespace std;const int maxn = 1000 + 10;const double PI = acos(-1);int n, T;double L;struct Point{double x, y;Point(double x = 0, double y = 0): x(x), y(y) {}};typedef Point Vector;typedef vector<Point> Polygon;Vector operator +(Vector A, Vector B)//{return Vector(A.x + B.x, A.y + B.y);}Vector operator -(Point A, Point B)//{return Vector(A.x - B.x , A.y - B.y);}Vector operator *(Vector A, double p)//{return Vector(A.x * p, A.y * p);}Vector operator /(Vector A, double p)//{return Vector(A.x / p, A.y / p);}bool operator <(const Point &a, const Point &b)//{return a.x < b.x || (a.x == b.x && a.y < b.y);}const double eps = 1e-10;int dcmp(double x)//{if (fabs(x) < eps) return 0;else return x < 0 ? -1 : 1;}bool operator ==(const Point &a, const Point &b)//{return dcmp(a.x - b.x) == 0 && dcmp(a.y - b.y) == 0;}Point read_point(){double X, Y;scanf("%lf%lf", &X, &Y);return Point(X, Y);}double Dot(Vector A, Vector B)//{return A.x * B.x + A.y * B.y;}double Length(Vector A)//{return sqrt(Dot(A, A));}double Cross(Vector A, Vector B)//{return A.x * B.y - A.y * B.x;}vector<Point> ConvexHull(vector<Point>& p){sort(p.begin(), p.end());p.erase(unique(p.begin(), p.end()), p.end());int n = p.size();int m = 0;vector<Point> ch(n + 1);for (int i = 0; i < n; i++){while (m > 1 && Cross(ch[m - 1] - ch[m - 2], p[i] - ch[m - 2]) <= 0) m--;ch[m++] = p[i];}int k = m;for (int i = n - 2; i >= 0; i--){while (m > k && Cross(ch[m - 1] - ch[m - 2], p[i] - ch[m - 2]) <= 0) m--;ch[m++] = p[i];}if (n > 1) m--;ch.resize(m);return ch;}Polygon P;int main(int argc, char const *argv[]){scanf("%d", &T);while (T--){scanf("%d%lf", &n, &L);for (int i = 0; i < n; i++)P.push_back(read_point());Polygon newp = ConvexHull(P);int lenn = newp.size();newp.push_back(newp.front());double ans = 0;for (int i = 0; i < lenn; i++)ans += Length(newp[i] - newp[i + 1]);ans += 2.0 * PI * L;printf("%.0lf\n", ans);if (T) printf("\n");}return 0;}
所有角加起来为360度，其余纯模板
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