三维凸包模板_Hdu 4273 Rescue
使用汝佳的模板: 简单,但是有的题目过不了
acm.hdu.edu.cn/showproblem.php?pid=4273
#include <cstdio>#include <ctime>#include <cstdlib>#include <cstring>#include <queue>#include <string>#include <set>#include <stack>#include <map>#include <cmath>#include <vector>#include <iostream>#include <algorithm>#include <bitset>#include <fstream>using namespace std;//LOOP#define FF(i, a, b) for(int i = (a); i < (b); ++i)#define FE(i, a, b) for(int i = (a); i <= (b); ++i)#define FED(i, b, a) for(int i = (b); i>= (a); --i)#define REP(i, N) for(int i = 0; i < (N); ++i)#define CLR(A,value) memset(A,value,sizeof(A))#define FC(it, c) for(__typeof((c).begin()) it = (c).begin(); it != (c).end(); it++)//OTHER#define SZ(V) (int)V.size()#define PB push_back#define MP make_pair#define all(x) (x).begin(),(x).end()//INPUT#define RI(n) scanf("%d", &n)#define RII(n, m) scanf("%d%d", &n, &m)#define RIII(n, m, k) scanf("%d%d%d", &n, &m, &k)#define RIV(n, m, k, p) scanf("%d%d%d%d", &n, &m, &k, &p)#define RV(n, m, k, p, q) scanf("%d%d%d%d%d", &n, &m, &k, &p, &q)#define RS(s) scanf("%s", s)//OUTPUT#define WI(n) printf("%d\n", n)#define WS(n) printf("%s\n", n)//debug//#define online_judge#ifndef online_judge#define debugt(a) cout << (#a) << "=" << a << " ";#define debugI(a) debugt(a) cout << endl#define debugII(a, b) debugt(a) debugt(b) cout << endl#define debugIII(a, b, c) debugt(a) debugt(b) debugt(c) cout << endl#define debugIV(a, b, c, d) debugt(a) debugt(b) debugt(c) debugt(d) cout << endl#else#define debugI(v)#define debugII(a, b)#define debugIII(a, b, c)#define debugIV(a, b, c, d)#endiftypedef long long LL;typedef unsigned long long ULL;typedef vector <int> VI;const int INF = 0x3f3f3f3f;const double eps = 1e-10;const int MOD = 100000007;const int MAXN = 400;const double PI = acos(-1.0);inline int dcmp(double x){ if(fabs(x) < eps) return 0; else return x < 0 ? -1 : 1;}struct Point{ double x, y, z; Point(double x=0, double y=0, double z=0):x(x),y(y),z(z) { } inline void read() { scanf("%lf%lf%lf", &x, &y, &z); }};typedef Point Vector;inline Vector operator + (Vector A, Vector B){ return Vector(A.x+B.x, A.y+B.y, A.z+B.z);}inline Vector operator - (Point A, Point B){ return Vector(A.x-B.x, A.y-B.y, A.z-B.z);}inline Vector operator * (Vector A, double p){ return Vector(A.x*p, A.y*p, A.z*p);}inline Vector operator / (Vector A, double p){ return Vector(A.x/p, A.y/p, A.z/p);}bool operator == (const Point& a, const Point& b){ return dcmp(a.x-b.x) == 0 && dcmp(a.y-b.y) == 0 && dcmp(a.z-b.z) == 0;}inline double Dot(Vector A, Vector B){ return A.x*B.x + A.y*B.y + A.z*B.z;}inline double Length(Vector A){ return sqrt(Dot(A, A));}inline double Angle(Vector A, Vector B){ return acos(Dot(A, B) / Length(A) / Length(B));}inline Vector Cross(Vector A, Vector B){ return Vector(A.y*B.z - A.z*B.y, A.z*B.x - A.x*B.z, A.x*B.y - A.y*B.x);}inline double Area2(Point A, Point B, Point C){ return Length(Cross(B-A, C-A));}inline double Volume6(Point A, Point B, Point C, Point D){ return Dot(D-A, Cross(B-A, C-A));}inline Point Centroid(Point A, Point B, Point C, Point D){ return (A + B + C + D)/4.0;}inline double rand01(){ return rand() / (double)RAND_MAX;}inline double randeps(){ return (rand01() - 0.5) * eps;}inline Point add_noise(Point p){ return Point(p.x + randeps(), p.y + randeps(), p.z + randeps());}struct Face{ int v[3]; Face(int a, int b, int c) { v[0] = a; v[1] = b; v[2] = c; } inline Vector Normal(const vector<Point>& P) const { return Cross(P[v[1]]-P[v[0]], P[v[2]]-P[v[0]]); } // f是否能看见P[i] inline int CanSee(const vector<Point>& P, int i) const { return Dot(P[i]-P[v[0]], Normal(P)) > 0; }};// 增量法求三维凸包// 注意：没有考虑各种特殊情况（如四点共面）。实践中，请在调用前对输入点进行微小扰动vector<Face> CH3D(const vector<Point>& P){ int n = P.size(); vector<vector<int> > vis(n); for(int i = 0; i < n; i++) vis[i].resize(n); vector<Face> cur; cur.push_back(Face(0, 1, 2)); // 由于已经进行扰动，前三个点不共线 cur.push_back(Face(2, 1, 0)); for(int i = 3; i < n; i++) { vector<Face> next; // 计算每条边的“左面”的可见性 for(int j = 0; j < (int)cur.size(); j++) { Face& f = cur[j]; int res = f.CanSee(P, i); if(!res) next.push_back(f); for(int k = 0; k < 3; k++) vis[f.v[k]][f.v[(k+1)%3]] = res; } for(int j = 0; j < (int)cur.size(); j++) for(int k = 0; k < 3; k++) { int a = cur[j].v[k], b = cur[j].v[(k+1)%3]; if(vis[a][b] != vis[b][a] && vis[a][b]) // (a,b)是分界线，左边对P[i]可见 next.push_back(Face(a, b, i)); } cur = next; } return cur;}struct ConvexPolyhedron{ int n; vector<Point> P, P2; vector<Face> faces; bool read() { if(scanf("%d", &n) != 1) return false; P.resize(n); P2.resize(n); for(int i = 0; i < n; i++) { P[i].read(); P2[i] = add_noise(P[i]); } faces = CH3D(P2); return true; } Point centroid() { Point C = P[0]; double totv = 0; Point tot(0,0,0); for(int i = 0; i < (int)faces.size(); i++) { Point p1 = P[faces[i].v[0]], p2 = P[faces[i].v[1]], p3 = P[faces[i].v[2]]; double v = -Volume6(p1, p2, p3, C); totv += v; tot = tot + Centroid(p1, p2, p3, C)*v; } return tot / totv; } double mindist(Point C) { double ans = 1e30; for(int i = 0; i < (int)faces.size(); i++) { Point p1 = P[faces[i].v[0]], p2 = P[faces[i].v[1]], p3 = P[faces[i].v[2]]; ans = min(ans, fabs(-Volume6(p1, p2, p3, C) / Area2(p1, p2, p3))); } return ans; }} P1;int main(){ ConvexPolyhedron P1, P2; while(P1.read()) { Point C1 = P1.centroid(); double d1 = P1.mindist(C1); printf("%.3lf\n", d1); } return 0;}