标签：sam define 投影 cross mes fine orm poi 检查
用类似归并排序的思想对两个凸包进行合并，合并完以后再求一次凸包
以下代码因使用浮点误差巨大
#include <bits/stdc++.h>
using namespace std;
#define mp make_pair
#define fi first
#define se second
#define pb push_back
typedef double db;
const db eps = 1e-9;
const db pi = acos(-1);
int sign(db k) {
if (k > eps) return 1; else if (k < -eps) return -1; return 0;
}
int cmp(db p1, db p2) { return sign(p1 - p2); }
int inmid(db p1, db p2, db p3) { return sign(p1 - p3) * sign(p2 - p3) <= 0; }// p3 在 [p1,p2] 内
struct point {
db x, y;
point operator + (const point& p1) const { return (point) { p1.x + x, p1.y + y }; }
point operator - (const point& p1) const { return (point) { x - p1.x, y - p1.y }; }
point operator * (db p1) const { return (point) { x* p1, y* p1 }; }
point operator / (db p1) const { return (point) { x / p1, y / p1 }; }
int operator == (const point& p1) const { return cmp(x, p1.x) == 0 && cmp(y, p1.y) == 0; }
// 逆时针旋转
point turn(db p1) { return (point) { x* cos(p1) - y * sin(p1), x* sin(p1) + y * cos(p1) }; }
point turn90() { return (point) { -y, x }; }
bool operator < (const point p1) const {
int a = cmp(x, p1.x);
if (a == -1) return 1; else if (a == 1) return 0; else return cmp(y, p1.y) == -1;
}
db abs() { return sqrt(x * x + y * y); }
db abs2() { return x * x + y * y; }
db dis(point p1) { return ((*this) - p1).abs(); }
point unit() { db w = abs(); return (point) { x / w, y / w }; }
void scan() { double p1, p2; scanf("%lf%lf", &p1, &p2); x = p1; y = p2; }
void print() { printf("%.11lf %.11lf\n", x, y); }
db getw() { return atan2(y, x); }
point getdel() { if (sign(x) == -1 || (sign(x) == 0 && sign(y) == -1)) return (*this) * (-1); else return (*this); }
int getP() const { return sign(y) == 1 || (sign(y) == 0 && sign(x) == -1); }
};
int inmid(point p1, point p2, point p3) { return inmid(p1.x, p2.x, p3.x) && inmid(p1.y, p2.y, p3.y); }
db cross(point p1, point p2) { return p1.x * p2.y - p1.y * p2.x; }
db dot(point p1, point p2) { return p1.x * p2.x + p1.y * p2.y; }
db rad(point p1, point p2) { return atan2(cross(p1, p2), dot(p1, p2)); }
// -pi -> pi
int compareangle(point p1, point p2) {
return p1.getP() < p2.getP() || (p1.getP() == p2.getP() && sign(cross(p1, p2)) > 0);
}
point proj(point p1, point p2, point q) { // q 到直线 p1,p2 的投影
point k = p2 - p1; return p1 + k * (dot(q - p1, k) / k.abs2());
}
point reflect(point p1, point p2, point q) { return proj(p1, p2, q) * 2 - q; }
int clockwise(point p1, point p2, point p3) {// p1 p2 p3 逆时针 1 顺时针 -1 否则 0
return sign(cross(p2 - p1, p3 - p1));
}
int checkLL(point p1, point p2, point p3, point p4) {// 求直线 (L) 线段 (S)p1,p2 和 p3,p4 的交点
return cmp(cross(p3 - p1, p4 - p1), cross(p3 - p2, p4 - p2)) != 0;
}
point getLL(point p1, point p2, point p3, point p4) {
db w1 = cross(p1 - p3, p4 - p3), w2 = cross(p4 - p3, p2 - p3); return (p1 * w2 + p2 * w1) / (w1 + w2);
}
int intersect(db l1, db r1, db l2, db r2) {
if (l1 > r1) swap(l1, r1); if (l2 > r2) swap(l2, r2); return cmp(r1, l2) != -1 && cmp(r2, l1) != -1;
}
int checkSS(point p1, point p2, point p3, point p4) {
return intersect(p1.x, p2.x, p3.x, p4.x) && intersect(p1.y, p2.y, p3.y, p4.y) &&
sign(cross(p3 - p1, p4 - p1)) * sign(cross(p3 - p2, p4 - p2)) <= 0 &&
sign(cross(p1 - p3, p2 - p3)) * sign(cross(p1 - p4, p2 - p4)) <= 0;
}
db disSP(point p1, point p2, point q) {
point p3 = proj(p1, p2, q);
if (inmid(p1, p2, p3)) return q.dis(p3); else return min(q.dis(p1), q.dis(p2));
}
db disSS(point p1, point p2, point p3, point p4) {
if (checkSS(p1, p2, p3, p4)) return 0;
else return min(min(disSP(p1, p2, p3), disSP(p1, p2, p4)), min(disSP(p3, p4, p1), disSP(p3, p4, p2)));
}
int onS(point p1, point p2, point q) { return inmid(p1, p2, q) && sign(cross(p1 - q, p2 - p1)) == 0; }
struct circle {
point o; db r;
void scan() { o.scan(); scanf("%lf", &r); }
int inside(point k) { return cmp(r, o.dis(k)); }
};
struct line {
// p[0]->p[1]
point p[2];
line(point p1, point p2) { p[0] = p1; p[1] = p2; }
point& operator [] (int k) { return p[k]; }
int include(point k) { return sign(cross(p[1] - p[0], k - p[0])) > 0; }
point dir() { return p[1] - p[0]; }
line push() { // 向外 ( 左手边 ) 平移 eps
const db eps = 1e-6;
point delta = (p[1] - p[0]).turn90().unit() * eps;
return { p[0] - delta,p[1] - delta };
}
};
point getLL(line p1, line p2) { return getLL(p1[0], p1[1], p2[0], p2[1]); }
int parallel(line p1, line p2) { return sign(cross(p1.dir(), p2.dir())) == 0; }
int sameDir(line p1, line p2) { return parallel(p1, p2) && sign(dot(p1.dir(), p2.dir())) == 1; }
int operator < (line p1, line p2) {
if (sameDir(p1, p2)) return p2.include(p1[0]);
return compareangle(p1.dir(), p2.dir());
}
int checkpos(line p1, line p2, line p3) { return p3.include(getLL(p1, p2)); }
vector<line> getHL(vector<line>& L) { // 求半平面交 , 半平面是逆时针方向 , 输出按照逆时针
sort(L.begin(), L.end()); deque<line> q;
for (int i = 0; i < (int)L.size(); i++) {
if (i && sameDir(L[i], L[i - 1])) continue;
while (q.size() > 1 && !checkpos(q[q.size() - 2], q[q.size() - 1], L[i])) q.pop_back();
while (q.size() > 1 && !checkpos(q[1], q[0], L[i])) q.pop_front();
q.push_back(L[i]);
}
while (q.size() > 2 && !checkpos(q[q.size() - 2], q[q.size() - 1], q[0])) q.pop_back();
while (q.size() > 2 && !checkpos(q[1], q[0], q[q.size() - 1])) q.pop_front();
vector<line>ans; for (int i = 0; i < q.size(); i++) ans.push_back(q[i]);
return ans;
}
db closepoint(vector<point>& A, int l, int r) { // 最近点对 , 先要按照 x 坐标排序
if (r - l <= 5) {
db ans = 1e20;
for (int i = l; i <= r; i++) for (int j = i + 1; j <= r; j++) ans = min(ans, A[i].dis(A[j]));
return ans;
}
int mid = l + r >> 1; db ans = min(closepoint(A, l, mid), closepoint(A, mid + 1, r));
vector<point>B; for (int i = l; i <= r; i++) if (abs(A[i].x - A[mid].x) <= ans) B.push_back(A[i]);
sort(B.begin(), B.end(), [](point p1, point p2) {return p1.y < p2.y; });
for (int i = 0; i < B.size(); i++) for (int j = i + 1; j < B.size() && B[j].y - B[i].y < ans; j++) ans = min(ans, B[i].dis(B[j]));
return ans;
}
int checkposCC(circle p1, circle p2) {// 返回两个圆的公切线数量
if (cmp(p1.r, p2.r) == -1) swap(p1, p2);
db dis = p1.o.dis(p2.o); int w1 = cmp(dis, p1.r + p2.r), w2 = cmp(dis, p1.r - p2.r);
if (w1 > 0) return 4; else if (w1 == 0) return 3; else if (w2 > 0) return 2;
else if (w2 == 0) return 1; else return 0;
}
vector<point> getCL(circle p1, point p2, point p3) { // 沿着 p2->p3 方向给出 , 相切给出两个
point k = proj(p2, p3, p1.o); db d = p1.r * p1.r - (k - p1.o).abs2();
if (sign(d) == -1) return {};
point del = (p3 - p2).unit() * sqrt(max((db)0.0, d)); return { k - del,k + del };
}
vector<point> getCC(circle p1, circle p2) {// 沿圆 p1 逆时针给出 , 相切给出两个
int pd = checkposCC(p1, p2); if (pd == 0 || pd == 4) return {};
db a = (p2.o - p1.o).abs2(), cosA = (p1.r * p1.r + a - p2.r * p2.r) / (2 * p1.r * sqrt(max(a, (db)0.0)));
db b = p1.r * cosA, c = sqrt(max((db)0.0, p1.r * p1.r - b * b));
point k = (p2.o - p1.o).unit(), m = p1.o + k * b, del = k.turn90() * c;
return { m - del,m + del };
}
vector<point> TangentCP(circle p1, point p2) {// 沿圆 p1 逆时针给出
db a = (p2 - p1.o).abs(), b = p1.r * p1.r / a, c = sqrt(max((db)0.0, p1.r * p1.r - b * b));
point k = (p2 - p1.o).unit(), m = p1.o + k * b, del = k.turn90() * c;
return { m - del,m + del };
}
vector<line> TangentoutCC(circle p1, circle p2) {
int pd = checkposCC(p1, p2); if (pd == 0) return {};
if (pd == 1) { point k = getCC(p1, p2)[0]; return { (line) { k,k } }; }
if (cmp(p1.r, p2.r) == 0) {
point del = (p2.o - p1.o).unit().turn90().getdel();
return { (line) { p1.o - del * p1.r,p2.o - del * p2.r },(line) { p1.o + del * p1.r,p2.o + del * p2.r } };
}
else {
point p = (p2.o * p1.r - p1.o * p2.r) / (p1.r - p2.r);
vector<point>A = TangentCP(p1, p), B = TangentCP(p2, p);
vector<line>ans; for (int i = 0; i < A.size(); i++) ans.push_back((line) { A[i], B[i] });
return ans;
}
}
vector<line> TangentinCC(circle p1, circle p2) {
int pd = checkposCC(p1, p2); if (pd <= 2) return {};
if (pd == 3) { point k = getCC(p1, p2)[0]; return { (line) { k,k } }; }
point p = (p2.o * p1.r + p1.o * p2.r) / (p1.r + p2.r);
vector<point>A = TangentCP(p1, p), B = TangentCP(p2, p);
vector<line>ans; for (int i = 0; i < A.size(); i++) ans.push_back((line) { A[i], B[i] });
return ans;
}
vector<line> TangentCC(circle p1, circle p2) {
int flag = 0; if (p1.r < p2.r) swap(p1, p2), flag = 1;
vector<line>A = TangentoutCC(p1, p2), B = TangentinCC(p1, p2);
for (line k : B) A.push_back(k);
if (flag) for (line& k : A) swap(k[0], k[1]);
return A;
}
db getarea(circle p1, point p2, point p3) {
// 圆 p1 与三角形 p2 p3 p1.o 的有向面积交
point k = p1.o; p1.o = p1.o - k; p2 = p2 - k; p3 = p3 - k;
int pd1 = p1.inside(p2), pd2 = p1.inside(p3);
vector<point>A = getCL(p1, p2, p3);
if (pd1 >= 0)
if (pd2 >= 0) return cross(p2, p3) / 2;
else return p1.r * p1.r * rad(A[1], p3) / 2 + cross(p2, A[1]) / 2;
else if (pd2 >= 0)
return p1.r * p1.r * rad(p2, A[0]) / 2 + cross(A[0], p3) / 2;
else
if (cmp(p1.r, disSP(p2, p3, p1.o)) <= 0) return p1.r * p1.r * rad(p2, p3) / 2;
else return cross(A[0], A[1]) / 2 + p1.r * p1.r * (rad(p2, A[0]) + rad(A[1], p3)) / 2;
}
circle getcircle(point p1, point p2, point p3) {
db a1 = p2.x - p1.x, b1 = p2.y - p1.y, c1 = (a1 * a1 + b1 * b1) / 2;
db a2 = p3.x - p1.x, b2 = p3.y - p1.y, c2 = (a2 * a2 + b2 * b2) / 2;
db d = a1 * b2 - a2 * b1;
point o = (point){ p1.x + (c1 * b2 - c2 * b1) / d,p1.y + (a1 * c2 - a2 * c1) / d };
return (circle) { o, p1.dis(o) };
}
circle getScircle(vector<point> A) {
random_shuffle(A.begin(), A.end());
circle ans = (circle){ A[0],0 };
for (int i = 1; i < A.size(); i++)
if (ans.inside(A[i]) == -1) {
ans = (circle){ A[i],0 };
for (int j = 0; j < i; j++)
if (ans.inside(A[j]) == -1) {
ans.o = (A[i] + A[j]) / 2; ans.r = ans.o.dis(A[i]);
for (int k = 0; k < j; k++)
if (ans.inside(A[k]) == -1)
ans = getcircle(A[i], A[j], A[k]);
}
}
return ans;
}
long long area(vector<point> A) { // 多边形用 vector<point> 表示 , 逆时针
long long ans = 0;
for (int i = 0; i < A.size(); i++) ans += cross(A[i], A[(i + 1) % A.size()]) + 0.5;
return ans;
}
int checkconvex(vector<point>A) {
int n = A.size(); A.push_back(A[0]); A.push_back(A[1]);
for (int i = 0; i < n; i++) if (sign(cross(A[i + 1] - A[i], A[i + 2] - A[i])) == -1) return 0;
return 1;
}
int contain(vector<point>A, point q) { // 2 内部 1 边界 0 外部
int pd = 0; A.push_back(A[0]);
for (int i = 1; i < A.size(); i++) {
point u = A[i - 1], v = A[i];
if (onS(u, v, q)) return 1; if (cmp(u.y, v.y) > 0) swap(u, v);
if (cmp(u.y, q.y) >= 0 || cmp(v.y, q.y) < 0) continue;
if (sign(cross(u - v, q - v)) < 0) pd ^= 1;
}
return pd << 1;
}
vector<point> ConvexHull(vector<point>A, int flag = 1) { // flag=0 不严格 flag=1 严格
int n = A.size(); vector<point>ans(n * 2);
sort(A.begin(), A.end()); int now = -1;
for (int i = 0; i < A.size(); i++) {
while (now > 0 && sign(cross(ans[now] - ans[now - 1], A[i] - ans[now - 1])) < flag) now--;
ans[++now] = A[i];
} int pre = now;
for (int i = n - 2; i >= 0; i--) {
while (now > pre && sign(cross(ans[now] - ans[now - 1], A[i] - ans[now - 1])) < flag) now--;
ans[++now] = A[i];
} ans.resize(now); return ans;
}
db convexDiameter(vector<point>A) {
int now = 0, n = A.size(); db ans = 0;
for (int i = 0; i < A.size(); i++) {
now = max(now, i);
while (1) {
db p1 = A[i].dis(A[now % n]), p2 = A[i].dis(A[(now + 1) % n]);
ans = max(ans, max(p1, p2)); if (p2 > p1) now++; else break;
}
}
return ans;
}
vector<point> convexcut(vector<point>A, point p1, point p2) {
// 保留 p1,p2,p 逆时针的所有点
int n = A.size(); A.push_back(A[0]); vector<point>ans;
for (int i = 0; i < n; i++) {
int w1 = clockwise(p1, p2, A[i]), w2 = clockwise(p1, p2, A[i + 1]);
if (w1 >= 0) ans.push_back(A[i]);
if (w1 * w2 < 0) ans.push_back(getLL(p1, p2, A[i], A[i + 1]));
}
return ans;
}
int checkPoS(vector<point>A, point p1, point p2) {
// 多边形 A 和直线 ( 线段 )p1->p2 严格相交 , 注释部分为线段
struct ins {
point m, u, v;
int operator < (const ins& k) const { return m < k.m; }
}; vector<ins>B;
//if (contain(A,p1)==2||contain(A,p2)==2) return 1;
vector<point>poly = A; A.push_back(A[0]);
for (int i = 1; i < A.size(); i++) if (checkLL(A[i - 1], A[i], p1, p2)) {
point m = getLL(A[i - 1], A[i], p1, p2);
if (inmid(A[i - 1], A[i], m)/*&&inmid(p1,p2,m)*/) B.push_back((ins) { m, A[i - 1], A[i] });
}
if (B.size() == 0) return 0; sort(B.begin(), B.end());
int now = 1; while (now < B.size() && B[now].m == B[0].m) now++;
if (now == B.size()) return 0;
int flag = contain(poly, (B[0].m + B[now].m) / 2);
if (flag == 2) return 1;
point d = B[now].m - B[0].m;
for (int i = now; i < B.size(); i++) {
if (!(B[i].m == B[i - 1].m) && flag == 2) return 1;
int tag = sign(cross(B[i].v - B[i].u, B[i].m + d - B[i].u));
if (B[i].m == B[i].u || B[i].m == B[i].v) flag += tag; else flag += tag * 2;
}
//return 0;
return flag == 2;
}
int checkinp(point r, point l, point m) {
if (compareangle(l, r)) { return compareangle(l, m) && compareangle(m, r); }
return compareangle(l, m) || compareangle(m, r);
}
int checkPosFast(vector<point>A, point p1, point p2) { // 快速检查线段是否和多边形严格相交
if (contain(A, p1) == 2 || contain(A, p2) == 2) return 1; if (p1 == p2) return 0;
A.push_back(A[0]); A.push_back(A[1]);
for (int i = 1; i + 1 < A.size(); i++)
if (checkLL(A[i - 1], A[i], p1, p2)) {
point now = getLL(A[i - 1], A[i], p1, p2);
if (inmid(A[i - 1], A[i], now) == 0 || inmid(p1, p2, now) == 0) continue;
if (now == A[i]) {
if (A[i] == p2) continue;
point pre = A[i - 1], ne = A[i + 1];
if (checkinp(pre - now, ne - now, p2 - now)) return 1;
}
else if (now == p1) {
if (p1 == A[i - 1] || p1 == A[i]) continue;
if (checkinp(A[i - 1] - p1, A[i] - p1, p2 - p1)) return 1;
}
else if (now == p2 || now == A[i - 1]) continue;
else return 1;
}
return 0;
}
// 拆分凸包成上下凸壳 凸包尽量都随机旋转一个角度来避免出现相同横坐标
// 尽量特判只有一个点的情况 凸包逆时针
void getUDP(vector<point>A, vector<point>& U, vector<point>& D) {
db l = 1e100, r = -1e100;
for (int i = 0; i < A.size(); i++) l = min(l, A[i].x), r = max(r, A[i].x);
int wherel, wherer;
for (int i = 0; i < A.size(); i++) if (cmp(A[i].x, l) == 0) wherel = i;
for (int i = A.size(); i; i--) if (cmp(A[i - 1].x, r) == 0) wherer = i - 1;
U.clear(); D.clear(); int now = wherel;
while (1) { D.push_back(A[now]); if (now == wherer) break; now++; if (now >= A.size()) now = 0; }
now = wherel;
while (1) { U.push_back(A[now]); if (now == wherer) break; now--; if (now < 0) now = A.size() - 1; }
}
// 需要保证凸包点数大于等于 3,2 内部 ,1 边界 ,0 外部
int containCoP(const vector<point>& U, const vector<point>& D, point k) {
db lx = U[0].x, rx = U[U.size() - 1].x;
if (k == U[0] || k == U[U.size() - 1]) return 1;
if (cmp(k.x, lx) == -1 || cmp(k.x, rx) == 1) return 0;
int where1 = lower_bound(U.begin(), U.end(), (point) { k.x, -1e100 }) - U.begin();
int where2 = lower_bound(D.begin(), D.end(), (point) { k.x, -1e100 }) - D.begin();
int w1 = clockwise(U[where1 - 1], U[where1], k), w2 = clockwise(D[where2 - 1], D[where2], k);
if (w1 == 1 || w2 == -1) return 0; else if (w1 == 0 || w2 == 0) return 1; return 2;
}
// d 是方向 , 输出上方切点和下方切点
pair<point, point> getTangentCow(const vector<point>& U, const vector<point>& D, point d) {
if (sign(d.x) < 0 || (sign(d.x) == 0 && sign(d.y) < 0)) d = d * (-1);
point whereU, whereD;
if (sign(d.x) == 0) return mp(U[0], U[U.size() - 1]);
int l = 0, r = U.size() - 1, ans = 0;
while (l < r) { int mid = l + r >> 1; if (sign(cross(U[mid + 1] - U[mid], d)) <= 0) l = mid + 1, ans = mid + 1; else r = mid; }
whereU = U[ans]; l = 0, r = D.size() - 1, ans = 0;
while (l < r) { int mid = l + r >> 1; if (sign(cross(D[mid + 1] - D[mid], d)) >= 0) l = mid + 1, ans = mid + 1; else r = mid; }
whereD = D[ans]; return mp(whereU, whereD);
}
// 先检查 contain, 逆时针给出
pair<point, point> getTangentCoP(const vector<point>& U, const vector<point>& D, point k) {
db lx = U[0].x, rx = U[U.size() - 1].x;
if (k.x < lx) {
int l = 0, r = U.size() - 1, ans = U.size() - 1;
while (l < r) { int mid = l + r >> 1; if (clockwise(k, U[mid], U[mid + 1]) == 1) l = mid + 1; else ans = mid, r = mid; }
point w1 = U[ans]; l = 0, r = D.size() - 1, ans = D.size() - 1;
while (l < r) { int mid = l + r >> 1; if (clockwise(k, D[mid], D[mid + 1]) == -1) l = mid + 1; else ans = mid, r = mid; }
point w2 = D[ans]; return mp(w1, w2);
}
else if (k.x > rx) {
int l = 1, r = U.size(), ans = 0;
while (l < r) { int mid = l + r >> 1; if (clockwise(k, U[mid], U[mid - 1]) == -1) r = mid; else ans = mid, l = mid + 1; }
point w1 = U[ans]; l = 1, r = D.size(), ans = 0;
while (l < r) { int mid = l + r >> 1; if (clockwise(k, D[mid], D[mid - 1]) == 1) r = mid; else ans = mid, l = mid + 1; }
point w2 = D[ans]; return mp(w2, w1);
}
else {
int where1 = lower_bound(U.begin(), U.end(), (point) { k.x, -1e100 }) - U.begin();
int where2 = lower_bound(D.begin(), D.end(), (point) { k.x, -1e100 }) - D.begin();
if ((k.x == lx && k.y > U[0].y) || (where1 && clockwise(U[where1 - 1], U[where1], k) == 1)) {
int l = 1, r = where1 + 1, ans = 0;
while (l < r) { int mid = l + r >> 1; if (clockwise(k, U[mid], U[mid - 1]) == 1) ans = mid, l = mid + 1; else r = mid; }
point w1 = U[ans]; l = where1, r = U.size() - 1, ans = U.size() - 1;
while (l < r) { int mid = l + r >> 1; if (clockwise(k, U[mid], U[mid + 1]) == 1) l = mid + 1; else ans = mid, r = mid; }
point w2 = U[ans]; return mp(w2, w1);
}
else {
int l = 1, r = where2 + 1, ans = 0;
while (l < r) { int mid = l + r >> 1; if (clockwise(k, D[mid], D[mid - 1]) == -1) ans = mid, l = mid + 1; else r = mid; }
point w1 = D[ans]; l = where2, r = D.size() - 1, ans = D.size() - 1;
while (l < r) { int mid = l + r >> 1; if (clockwise(k, D[mid], D[mid + 1]) == -1) l = mid + 1; else ans = mid, r = mid; }
point w2 = D[ans]; return mp(w1, w2);
}
}
}
struct P3 {
db x, y, z;
P3 operator + (P3 p1) { return (P3) { x + p1.x, y + p1.y, z + p1.z }; }
P3 operator - (P3 p1) { return (P3) { x - p1.x, y - p1.y, z - p1.z }; }
P3 operator * (db p1) { return (P3) { x* p1, y* p1, z* p1 }; }
P3 operator / (db p1) { return (P3) { x / p1, y / p1, z / p1 }; }
db abs2() { return x * x + y * y + z * z; }
db abs() { return sqrt(x * x + y * y + z * z); }
P3 unit() { return (*this) / abs(); }
int operator < (const P3 p1) const {
if (cmp(x, p1.x) != 0) return x < p1.x;
if (cmp(y, p1.y) != 0) return y < p1.y;
return cmp(z, p1.z) == -1;
}
int operator == (const P3 p1) {
return cmp(x, p1.x) == 0 && cmp(y, p1.y) == 0 && cmp(z, p1.z) == 0;
}
void scan() {
double p1, p2, p3; scanf("%lf%lf%lf", &p1, &p2, &p3);
x = p1; y = p2; z = p3;
}
};
P3 cross(P3 p1, P3 p2) { return (P3) { p1.y* p2.z - p1.z * p2.y, p1.z* p2.x - p1.x * p2.z, p1.x* p2.y - p1.y * p2.x }; }
db dot(P3 p1, P3 p2) { return p1.x * p2.x + p1.y * p2.y + p1.z * p2.z; }
//p=(3,4,5),l=(13,19,21),theta=85 ans=(2.83,4.62,1.77)
P3 turn3D(db p1, P3 l, P3 p) {
l = l.unit(); P3 ans; db c = cos(p1), s = sin(p1);
ans.x = p.x * (l.x * l.x * (1 - c) + c) + p.y * (l.x * l.y * (1 - c) - l.z * s) + p.z * (l.x * l.z * (1 - c) + l.y * s);
ans.y = p.x * (l.x * l.y * (1 - c) + l.z * s) + p.y * (l.y * l.y * (1 - c) + c) + p.z * (l.y * l.z * (1 - c) - l.x * s);
ans.z = p.x * (l.x * l.z * (1 - c) - l.y * s) + p.y * (l.y * l.z * (1 - c) + l.x * s) + p.z * (l.x * l.x * (1 - c) + c);
return ans;
}
typedef vector<P3> VP;
typedef vector<VP> VVP;
db Acos(db x) { return acos(max(-(db)1, min(x, (db)1))); }
// 球面距离 , 圆心原点 , 半径 1
db Odist(P3 a, P3 b) { db r = Acos(dot(a, b)); return r; }
db r; P3 rnd;
vector<db> solve(db a, db b, db c) {
db r = sqrt(a * a + b * b), th = atan2(b, a);
if (cmp(c, -r) == -1) return { 0 };
else if (cmp(r, c) <= 0) return { 1 };
else {
db tr = pi - Acos(c / r); return { th + pi - tr,th + pi + tr };
}
}
vector<db> jiao(P3 a, P3 b) {
// dot(rd+x*cos(t)+y*sin(t),b) >= cos(r)
if (cmp(Odist(a, b), 2 * r) > 0) return { 0 };
P3 rd = a * cos(r), z = a.unit(), y = cross(z, rnd).unit(), x = cross(y, z).unit();
vector<db> ret = solve(-(dot(x, b) * sin(r)), -(dot(y, b) * sin(r)), -(cos(r) - dot(rd, b)));
return ret;
}
db norm(db x, db l = 0, db r = 2 * pi) { // change x into [l,r)
while (cmp(x, l) == -1) x += (r - l); while (cmp(x, r) >= 0) x -= (r - l);
return x;
}
db disLP(P3 p1, P3 p2, P3 q) {
return (cross(p2 - p1, q - p1)).abs() / (p2 - p1).abs();
}
db disLL(P3 p1, P3 p2, P3 p3, P3 p4) {
P3 dir = cross(p2 - p1, p4 - p3); if (sign(dir.abs()) == 0) return disLP(p1, p2, p3);
return fabs(dot(dir.unit(), p1 - p2));
}
VP getFL(P3 p, P3 dir, P3 p1, P3 p2) {
db a = dot(p2 - p, dir), b = dot(p1 - p, dir), d = a - b;
if (sign(fabs(d)) == 0) return {};
return { (p1 * a - p2 * b) / d };
}
VP getFF(P3 p1, P3 dir1, P3 p2, P3 dir2) {// 返回一条线
P3 e = cross(dir1, dir2), v = cross(dir1, e);
db d = dot(dir2, v); if (sign(abs(d)) == 0) return {};
P3 q = p1 + v * dot(dir2, p2 - p1) / d; return { q,q + e };
}
// 3D Covex Hull Template
db getV(P3 p1, P3 p2, P3 p3, P3 p4) { // get the Volume
return dot(cross(p2 - p1, p3 - p1), p4 - p1);
}
db rand_db() { return 1.0 * rand() / RAND_MAX; }
VP convexHull2D(VP A, P3 dir) {
P3 x = { (db)rand(),(db)rand(),(db)rand() }; x = x.unit();
x = cross(x, dir).unit(); P3 y = cross(x, dir).unit();
P3 vec = dir.unit() * dot(A[0], dir);
vector<point>B;
for (int i = 0; i < A.size(); i++) B.push_back((point) { dot(A[i], x), dot(A[i], y) });
B = ConvexHull(B); A.clear();
for (int i = 0; i < B.size(); i++) A.push_back(x * B[i].x + y * B[i].y + vec);
return A;
}
namespace CH3 {
VVP ret; set<pair<int, int> >e;
int n; VP p, q;
void wrap(int a, int b) {
if (e.find({ a,b }) == e.end()) {
int c = -1;
for (int i = 0; i < n; i++) if (i != a && i != b) {
if (c == -1 || sign(getV(q[c], q[a], q[b], q[i])) > 0) c = i;
}
if (c != -1) {
ret.push_back({ p[a],p[b],p[c] });
e.insert({ a,b }); e.insert({ b,c }); e.insert({ c,a });
wrap(c, b); wrap(a, c);
}
}
}
VVP ConvexHull3D(VP _p) {
p = q = _p; n = p.size();
ret.clear(); e.clear();
for (auto& i : q) i = i + (P3) { rand_db() * 1e-4, rand_db() * 1e-4, rand_db() * 1e-4 };
for (int i = 1; i < n; i++) if (q[i].x < q[0].x) swap(p[0], p[i]), swap(q[0], q[i]);
for (int i = 2; i < n; i++) if ((q[i].x - q[0].x) * (q[1].y - q[0].y) > (q[i].y - q[0].y) * (q[1].x - q[0].x)) swap(q[1], q[i]), swap(p[1], p[i]);
wrap(0, 1);
return ret;
}
}
VVP reduceCH(VVP A) {
VVP ret; map<P3, VP> M;
for (VP nowF : A) {
P3 dir = cross(nowF[1] - nowF[0], nowF[2] - nowF[0]).unit();
for (P3 p1 : nowF) M[dir].pb(p1);
}
for (pair<P3, VP> nowF : M) ret.pb(convexHull2D(nowF.se, nowF.fi));
return ret;
}
// 把一个面变成 ( 点 , 法向量 ) 的形式
pair<P3, P3> getF(VP F) {
return mp(F[0], cross(F[1] - F[0], F[2] - F[0]).unit());
}
// 3D Cut 保留 dot(dir,x-p)>=0 的部分
VVP ConvexCut3D(VVP A, P3 p, P3 dir) {
VVP ret; VP sec;
for (VP nowF : A) {
int n = nowF.size(); VP ans; int dif = 0;
for (int i = 0; i < n; i++) {
int d1 = sign(dot(dir, nowF[i] - p));
int d2 = sign(dot(dir, nowF[(i + 1) % n] - p));
if (d1 >= 0) ans.pb(nowF[i]);
if (d1 * d2 < 0) {
P3 q = getFL(p, dir, nowF[i], nowF[(i + 1) % n])[0];
ans.push_back(q); sec.push_back(q);
}
if (d1 == 0) sec.push_back(nowF[i]); else dif = 1;
dif |= (sign(dot(dir, cross(nowF[(i + 1) % n] - nowF[i], nowF[(i + 1) % n] - nowF[i]))) == -1);
}
if (ans.size() > 0 && dif) ret.push_back(ans);
}
if (sec.size() > 0) ret.push_back(convexHull2D(sec, dir));
return ret;
}
db vol(VVP A) {
if (A.size() == 0) return 0; P3 p = A[0][0]; db ans = 0;
for (VP nowF : A)
for (int i = 2; i < nowF.size(); i++)
ans += abs(getV(p, nowF[0], nowF[i - 1], nowF[i]));
return ans / 6;
}
VVP init(db INF) {
VVP pss(6, VP(4));
pss[0][0] = pss[1][0] = pss[2][0] = { -INF, -INF, -INF };
pss[0][3] = pss[1][1] = pss[5][2] = { -INF, -INF, INF };
pss[0][1] = pss[2][3] = pss[4][2] = { -INF, INF, -INF };
pss[0][2] = pss[5][3] = pss[4][1] = { -INF, INF, INF };
pss[1][3] = pss[2][1] = pss[3][2] = { INF, -INF, -INF };
pss[1][2] = pss[5][1] = pss[3][3] = { INF, -INF, INF };
pss[2][2] = pss[4][3] = pss[3][1] = { INF, INF, -INF };
pss[5][0] = pss[4][0] = pss[3][0] = { INF, INF, INF };
return pss;
}
vector <point> minksum(vector <point> a,vector <point> b) {
a.push_back(a[0]);
b.push_back(b[0]);
vector<point> c;
int p1=0,p2=0;
while(p1<a.size() && p2<b.size()) {
point v1=a[p1+1]-a[p1],v2=b[p2+1]-b[p2];
if(cross(v1,v2)>0) ++p1;
else ++p2;
c.push_back(a[p1]+b[p2]);
}
while(p1<a.size()) ++p1, c.push_back(a[p1]+b[p2]);
while(p2<b.size()) ++p2, c.push_back(a[p1]+b[p2]);
return ConvexHull(c);
}
int main() {
ios::sync_with_stdio(false);
int n,m;
point t;
vector<point> a,b;
scanf("%d%d",&n,&m);
for(int i=1;i<=n;i++) {
t.scan();
a.push_back(t);
}
for(int i=1;i<=m;i++) {
t.scan();
b.push_back(t);
}
a=ConvexHull(a);
b=ConvexHull(b);
vector<point> c=minksum(a,b);
cout<<(long long)(area(c));
}
标签：sam define 投影 cross mes fine orm poi 检查
原文地址：https://www.cnblogs.com/mollnn/p/12455179.html
