UVA10652 Board Wrapping (二維凸包+多邊形面積)
阿新 • • 發佈:2021-10-02
題目連結:https://www.luogu.com.cn/problem/UVA10652
#include<bits/stdc++.h> using namespace std; typedef long long ll; const int maxn = 5010; const double eps = 1e-10; const double PI = acos(-1.0); int T, n; int dcmp(double x) { if(fabs(x) < eps) return 0; else return x < 0 ? -1 : 1; } struct Point { double x, y; Point(double x=0, double y=0):x(x),y(y) { } }; bool operator < (const Point& a, const Point& b) { return a.x < b.x || (a.x == b.x && a.y < b.y); } bool operator == (const Point& a, const Point &b) { return dcmp(a.x-b.x) == 0 && dcmp(a.y-b.y) == 0; } typedef Point Vector; Vector operator + (const Vector& A, const Vector& B) { return Vector(A.x+B.x, A.y+B.y); } Vector operator - (const Point& A, const Point& B) { return Vector(A.x-B.x, A.y-B.y); } Vector operator * (const Vector& A, double p) { return Vector(A.x*p, A.y*p); } double Dot(const Vector& A, const Vector& B) { return A.x*B.x + A.y*B.y; } double Length(const Vector& A) { return sqrt(Dot(A, A)); } double Angle(const Vector& A, const Vector& B) { return acos(Dot(A, B) / Length(A) / Length(B)); } double Cross(const Vector& A, const Vector& B) { return A.x*B.y - A.y*B.x; } double torad(double x){ return x / 180 * PI; } bool SegmentProperIntersection(const Point& a1, const Point& a2, const Point& b1, const Point& b2) { double c1 = Cross(a2-a1,b1-a1), c2 = Cross(a2-a1,b2-a1), c3 = Cross(b2-b1,a1-b1), c4=Cross(b2-b1,a2-b1); return dcmp(c1)*dcmp(c2)<0 && dcmp(c3)*dcmp(c4)<0; } Point GetLineIntersection(const Point& P, const Point& v, const Point& Q, const Point& w) { Vector u = P-Q; double t = Cross(w, u) / Cross(v, w); return P+v*t; } Vector Rotate(const Vector& A, double rad) { return Vector(A.x*cos(rad)-A.y*sin(rad), A.x*sin(rad)+A.y*cos(rad)); } bool OnSegment(const Point& p, const Point& a1, const Point& a2) { return dcmp(Cross(a1-p, a2-p)) == 0 && dcmp(Dot(a1-p, a2-p)) < 0; } int pc, m; Point p[maxn], ch[maxn]; void ConvexHull(){ for(int i = 1 ; i <= pc ; ++i){ while(m >= 2 && dcmp(Cross(ch[m]-ch[m-1], p[i]-ch[m-1])) <= 0) --m; ch[++m] = p[i]; } int k = m; for(int i = pc-1 ; i >= 1 ; --i){ while(m >= k+1 && dcmp(Cross(ch[m]-ch[m-1], p[i]-ch[m-1])) <= 0) --m; ch[++m] = p[i]; } if(n > 1) --m; } double Polyarea(){ double area = 0; for(int i = 2 ; i < m ; ++i){ area += Cross(ch[i]-ch[1], ch[i+1]-ch[1]); } return area; } ll read(){ ll s = 0, f = 1; char ch = getchar(); while(ch < '0' || ch > '9'){ if(ch == '-') f = -1; ch = getchar(); } while(ch >= '0' && ch <= '9'){ s = s * 10 + ch - '0'; ch = getchar(); } return s * f; } int main(){ scanf("%d", &T); while(T--){ pc = 0, m = 0; scanf("%d", &n); double x, y, w, h, j; double area1 = 0, area2 = 0; for(int i = 1 ; i <= n ; ++i){ scanf("%lf%lf%lf%lf%lf", &x, &y, &w, &h, &j); double ang = -torad(j); Point o(x, y); p[++pc] = o + Rotate(Vector(w/2, h/2), ang); p[++pc] = o + Rotate(Vector(w/2, -h/2), ang); p[++pc] = o + Rotate(Vector(-w/2, h/2), ang); p[++pc] = o + Rotate(Vector(-w/2, -h/2), ang); area1 += w*h; } sort(p+1, p+1+pc); pc = unique(p+1, p+1+pc)-p-1; ConvexHull(); area2 = Polyarea(); area2 /= 2.0; printf("%.1lf %%\n", (area1*100/area2)); } return 0; }