本文主要是介绍【UVA】10652-Board Wrapping（凸包问题），希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
又增加了2个模板。
#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <string>
#include <cstring>
#include <cmath>
#include <vector>
#include <queue>
#include <stack>
#include <algorithm>
using namespace std;
const double eps = 1e-10;
#define MAXD 3000
#define _PI acos(-1.0)
struct Point
{double x, y;Point(double x = 0, double y = 0) : x(x), y(y) { }bool operator < (const Point& a) const{if(a.x != x) return x < a.x;return y < a.y;}
};typedef Point Vector;
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); }
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;
}
double Dot(Vector A, Vector B) { return A.x*B.x + A.y*B.y; }
double Dist(Point A,Point B){return sqrt((A.x - B.x) * (A.x - B.x) + (A.y - B.y) * (A.y - B.y));}
double Length(Vector A) { return sqrt(Dot(A, A)); }
double Angle(Vector A, Vector B) { return acos(Dot(A, B) / Length(A) / Length(B)); }
double Cross(Vector A, Vector B) { return A.x*B.y - A.y*B.x; }
double Area2(Point A, Point B, Point C) { return Cross(B-A, C-A); }
Vector Rotate(Vector A, double rad)
{return Vector(A.x*cos(rad)-A.y*sin(rad), A.x*sin(rad) + A.y*cos(rad));
}
double DistToSegment(Point P,Point A,Point B){if(A == B) return Length(P - A);Vector v1 = B - A , v2 = P - A , v3 = P - B;if(dcmp(Dot(v1,v2)) < 0) return Length(v2);if(dcmp(Dot(v1,v3)) > 0) return Length(v3);return fabs(Cross(v1,v2) / Length(v1));
}
Point GetIntersection(Point P, Vector v, Point Q, Vector w)
{Vector u = P-Q;double t = Cross(w, u) / Cross(v, w);return P+v*t;
}
bool SegmentProperIntersection(Point a1, Point a2, Point b1, Point b2)
{double c1 = Cross(a2-a1, b1-a1), c2 = Cross(a2-a1, b2-a1);double c3 = Cross(b2-b1, a1-b1), c4 = Cross(b2-b1, a2-b1);return dcmp(c1) * dcmp(c2) < 0 && dcmp(c3) * dcmp(c4) < 0;
}
double PolygonArea(Point* p, int n)
{double area = 0;for(int i = 1; i < n-1; i++)area += Cross(p[i]-p[0], p[i+1]-p[0]);return area;
}
bool OnSegment(Point p, Point a1, Point a2)
{return dcmp(Cross(a1-p, a2-p)) == 0 && dcmp(Dot(a1-p, a2-p)) < 0;
}
double PloygonArea(Point *p,int n){double area = 0;for(int i = 0 ; i < n ; i++){area += Cross(p[i] - p[0],p[i + 1] - p[0]);}return area / 2;
}
int ConvexHull(Point *p,int n,Point *ch){sort(p,p + n);int m = 0;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 --;return m;
}
int main(){int T;scanf("%d",&T);Point p[MAXD];Point ans[MAXD];while(T--){int n;scanf("%d",&n);double x,y,H,W,rad;double area = 0;int num = 0;Point o;for(int i = 0 ; i < n ; i ++){scanf("%lf%lf%lf%lf%lf",&o.x,&o.y,&W,&H,&rad);rad = -(rad * _PI / 180);p[num++] = o + Rotate(Vector(-W/2,-H/2),rad);p[num++] = o + Rotate(Vector(W/2,-H/2),rad);p[num++] = o + Rotate(Vector(-W/2,H/2),rad);p[num++] = o + Rotate(Vector(W/2,H/2),rad);area += W * H;}int m = ConvexHull(p,num,ans);double area2 = PloygonArea(ans,m);printf("%.1f %%\n",area * 100 / area2);}return 0;
}
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