直线相交 POJ 1269
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1 // 直线相交 POJ 1269 2 3 // #include <bits/stdc++.h> 4 #include <iostream> 5 #include <cstdio> 6 #include <cstdlib> 7 #include <algorithm> 8 #include <math.h> 9 using namespace std; 10 #define LL long long 11 typedef pair<int,int> pii; 12 const double inf = 123456789012345.0; 13 const LL MOD =100000000LL; 14 const int N =1e4+10; 15 #define clc(a,b) memset(a,b,sizeof(a)) 16 const double eps = 1e-8; 17 void fre() {freopen("in.txt","r",stdin);} 18 void freout() {freopen("out.txt","w",stdout);} 19 inline int read() {int x=0,f=1;char ch=getchar();while(ch>‘9‘||ch<‘0‘) {if(ch==‘-‘) f=-1; ch=getchar();}while(ch>=‘0‘&&ch<=‘9‘) {x=x*10+ch-‘0‘;ch=getchar();}return x*f;} 20 21 int sgn(double x){ 22 if(fabs(x) < eps)return 0; 23 if(x < 0)return -1; 24 else return 1; 25 } 26 struct Point{ 27 double x,y; 28 Point(){} 29 Point(double _x,double _y){ 30 x = _x;y = _y; 31 } 32 Point operator -(const Point &b)const{ 33 return Point(x - b.x,y - b.y); 34 } 35 double operator ^(const Point &b)const{ 36 return x*b.y - y*b.x; 37 } 38 double operator *(const Point &b)const{ 39 return x*b.x + y*b.y; 40 } 41 }; 42 43 struct Line{ 44 Point s,e; 45 Line(){} 46 Line(Point _s,Point _e){ 47 s=_s;e=_e; 48 } 49 pair<int,Point> operator & (const Line &b) const{ 50 Point res=s; 51 if(sgn((s-e)^(b.s-b.e))==0){ 52 if(sgn((s-b.e)^(b.s-b.e))==0) 53 return make_pair(0,res); 54 else return make_pair(1,res); 55 } 56 double t=((s-b.s)^(b.s-b.e))/((s-e)^(b.s-b.e)); 57 res.x+=(e.x-s.x)*t; 58 res.y+=(e.y-s.y)*t; 59 return make_pair(2,res); 60 } 61 }; 62 63 int main(){ 64 int T; 65 scanf("%d",&T); 66 double x1,x2,x3,x4,y1,y2,y3,y4; 67 printf("INTERSECTING LINES OUTPUT\n"); 68 while(T--){ 69 scanf("%lf%lf%lf%lf%lf%lf%lf%lf",&x1,&y1,&x2,&y2,&x3,&y3,&x4,&y4); 70 Line line1 = Line(Point(x1,y1),Point(x2,y2)); 71 Line line2 = Line(Point(x3,y3),Point(x4,y4)); 72 pair<int,Point> ans=line1 & line2; 73 if(ans.first==0) printf("LINE\n"); 74 else if(ans.first==1) printf("NONE\n"); 75 else printf("POINT %.2f %.2f\n",ans.second.x,ans.second.y); 76 } 77 printf("END OF OUTPUT\n"); 78 return 0; 79 }
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