题目地址:POJ 1269
直接套模板就可以了。。。实在不想自己写模板了。。。写的又臭又长。。。。不过这题需要注意的是要先判断是否有直线垂直X轴的情况。
代码如下:
#include <iostream> #include <cstdio> #include <string> #include <cstring> #include <stdlib.h> #include <math.h> #include <ctype.h> #include <queue> #include <map> #include <set> #include <algorithm> using namespace std; #define eqs 1e-10 struct node { double x, y; }point; int dcmp(double x, double y) { if(fabs(x-y)<=eqs) return 1; return 0; } node intersection(node u1, node u2, node v1, node v2) { node 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; } int main() { int n, i; printf("INTERSECTING LINES OUTPUT\n"); scanf("%d",&n); node f1, f2, f3, f4; while(n--) { scanf("%lf%lf%lf%lf%lf%lf%lf%lf",&f1.x,&f1.y,&f2.x,&f2.y,&f3.x,&f3.y,&f4.x,&f4.y); node a, b; a.x=f2.x-f1.x; a.y=f2.y-f1.y; b.x=f4.x-f3.x; b.y=f4.y-f3.y; if(dcmp(f1.x,f2.x)&&dcmp(f3.x,f4.x)) { if(f1.x==f3.x) { printf("LINE\n"); } else { printf("NONE\n"); } continue ; } else if(dcmp(f1.x,f2.x)) { double k=b.y/b.x; double b=f3.y-(f3.x*k); double y=k*f1.x+b; printf("POINT %.2lf %.2lf\n",f1.x,y); continue ; } else if(dcmp(f3.x,f4.x)) { double k=b.y/b.x; double b=f1.y-(f1.x*k); double y=k*f3.x+b; printf("POINT %.2lf %.2lf\n",f3.x,y); continue ; } double k1=a.y/a.x; double k2=b.y/b.x; double b1=f1.y-(k1*f1.x); double b2=f3.y-(k2*f3.x); if(dcmp(k1,k2)) { if(dcmp(b1,b2)) { printf("LINE\n"); } else printf("NONE\n"); } else { node ff=intersection(f1,f2,f3,f4); printf("POINT %.2lf %.2lf\n",ff.x,ff.y); } } printf("END OF OUTPUT\n"); return 0; }