uva 10256 凸包

#include <bits/stdc++.h>using namespace std;int n, m;double x, y;const double eps = 1e-10;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) {}};typedef Point Vector;Vector operator-(Vector A, Vector B){return Vector(A.x - B.x, A.y - B.y);}Vector operator+(Vector A, Vector B){return Vector(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;}double Dot(Vector A, Vector B){return A.x * B.x + A.y * B.y;}double Cross(Vector A, Vector B){return A.x * B.y - A.y * B.x;}bool operator<(const Point&a, const Point &b){return a.x < b.x || (a.x == b.x && a.y < b.y);}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;}bool OnSegment(Point p, Point a1, Point a2){return dcmp(Cross(a1 - p, a2 - p)) == 0 && dcmp(Dot(a1 - p, a2 - p)) < 0;}typedef vector<Point> Polygon;int isPointInPolygon(Point p, Polygon poly){int wn = 0;int n = poly.size();for (int i = 0; i < n; i++){if ( poly[i] == p || poly[(i + 1) % n] == p || OnSegment(p,  poly[i], poly[(i + 1) % n])) return -1;int k = dcmp(Cross(poly[(i + 1) % n] - poly[i], p - poly[i]));int d1 = dcmp(poly[i].y - p.y);int d2 = dcmp(poly[(i + 1) % n].y - p.y);if (k > 0 && d1 <= 0 && d2 > 0) wn++;if (k < 0 && d2 <= 0 && d1 > 0) wn--;}if (wn != 0) return 1;return 0;}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;}bool ConvexPolygonDisjoint(const Polygon p1, const Polygon p2){int c1 = p1.size();int c2 = p2.size();for (int i = 0; i < c1; i++)if (isPointInPolygon(p1[i], p2)) return false;for (int i = 0; i < c2; i++)if (isPointInPolygon(p2[i], p1)) return false;for (int i = 0; i < c1; i++)for (int j = 0; j < c2; j++)if (SegmentProperIntersection(p1[i], p1[(i + 1) % c1], p2[j], p2[(j + 1) % c2]))  return false;return true;}int main(int argc, char const *argv[]){while (scanf("%d%d", &n, &m) != EOF){if (n == 0 && m == 0) break;std::vector<Point> p1, p2;for (int i = 0; i < n; i++){scanf("%lf%lf", &x, &y);p1.push_back(Point(x, y));}for (int i = 0; i < m; i++){scanf("%lf%lf", &x, &y);p2.push_back(Point(x, y));}printf("%s\n", (ConvexPolygonDisjoint(ConvexHull(p1), ConvexHull(p2)) ? "Yes" : "No"));}return 0;}

求出两凸包，暴力判断是否相交，

退化为点或线段的情况一样处理，只要碰到另一个就是NO。