Poj 3335 rotating Scoreboard-semi-plane intersection

/* Poj 3335 rotating Scoreboard-the semi-plane intersection point is clockwise */# include <stdio. h> # include <math. h> const double EPS = 1e-8; const int n = 103; struct point {Double X, Y;} Dian [N]; inline bool mo_ee (Double X, Double Y) {double ret = x-y; If (Ret <0) ret =-ret; If (Ret <EPS) return 1; return 0;} inline bool mo_gg (Double X, double Y) {return x> Y + EPS;} // x> yinline bool mo_ll (Double X, Double Y) {return x <Y-EPS ;} // x <yinline bool mo_ge (Double X, Double Y) {return x> Y-EPS;} // x> = yinline bool mo_le (Double X, Double Y) {return x <Y + EPS;} // x <= yinline double mo_xmult (point P2, point P0, Point P1) // P1 returns a negative value on the left of P2, return positive {return (p1.x-0000x) * (p2.y-0000y)-(p2.x-0000x) * (p1.y-0000y) on the Right );} // calculate the Polygon Area Double mo_area_polygon (point * Dian, int N) {int I; point yuan; yuan. X = yuan. y = 0; double ret = 0; for (I = 0; I <n; ++ I) {RET + = mo_xmult (Dian [(I + 1) % N], yuan, Dian [I]);} return ret;} Point mo_intersection (point u1, point U2, point V1, point V2) {point ret = U1; double T = (u1.x-v1.x) * (v1.y-v2.y)-(u1.y-v1.y) * (v1.x-v2.x)/(u1.x-u2.x) * (v1.y-v2.y)-(u1.y-u2.y) * (v1.x-v2.x); ret. X + = (u2.x-u1.x) * t; ret. Y + = (u2.y-u1.y) * t; return ret ;} /////////////// // obtain the semi-plane intersection point mo_banjiao_jiao [N * 2] by the cutting method. point mo_banjiao_jiao_temp [N * 2]; void mo_banjiao_cut (point * ans, point Qian, point Hou, Int & nofdian) {int I, K; for (I = k = 0; I <nofdian; ++ I) {double A, B; A = mo_xmult (Hou, ANS [I], Qian); B = mo_xmult (Hou, ans [(I + 1) % nofdian], Qian); If (mo_ge (A, 0 )) // clockwise <= 0 {mo_banjiao_jiao_temp [k ++] = ans [I];} If (mo_ll (A * B, 0 )) {mo_banjiao_jiao_temp [k ++] = mo_intersection (Qian, Hou, ANS [I], ANS [(I + 1) % nofdian]) ;}} for (I = 0; I <K; ++ I) {ans [I] = mo_banjiao_jiao_temp [I];} nofdian = K;} int mo_banjiao (point * Dian, int N) {int I, nofdian; double area = mo_area_polygon (Dian, n); If (area <0) {point temp; int Zhong = n/2-1; for (I = 0; I <= Zhong; ++ I) {temp = Dian [I]; DIAN [I] = Dian [n-1-i]; DIAN [n-1-i] = temp ;}} nofdian = N; for (I = 0; I <n; ++ I) {mo_banjiao_jiao [I] = Dian [I] ;}for (I = 0; I <n; ++ I) {mo_banjiao_cut (mo_banjiao_jiao, Dian [I], Dian [(I + 1) % N], nofdian); If (nofdian = 0) {return nofdian ;}} return nofdian;} // int main () {int T, I, n; scanf ("% d", & T); While (t --) {scanf ("% d", & N); for (I = 0; I <N; ++ I) {scanf ("% lf", & Dian [I]. x, & Dian [I]. y);} int ret = mo_banjiao (Dian, n); If (ret = 0) {printf ("NO \ n ");} else {printf ("Yes \ n") ;}} return 0 ;}