HDU1174+三维点到直线距离

点B到直线AC的距离 就是 |AB X AC|/|AC|   ‘X’是叉乘   ’ || ‘表示模

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 1 /*

 2 三维+点到直线的距离

 3 */

 4 #include<stdio.h>

 5 #include<string.h>

 6 #include<stdlib.h>

 7 #include<algorithm>

 8 #include<iostream>

 9 #include<queue>

10 //#include<map>

11 #include<math.h>

12 using namespace std;

13 typedef long long ll;

14 //typedef __int64 int64;

15 const int maxn = 105;

16 const int inf = 0x7fffffff;

17 const double pi=acos(-1.0);

18 const double eps = 1e-8;

19 struct point {

20     double x,y,z;

21 };

22 struct line{

23     double a,b,c,d;

24 };//ax+by+cz+d=0;

25 struct people{

26     double hi,r,x,y,z;

27 };

28 double fpow( double x ){

29     return x*x;

30 }

31 int main(){

32     int ca;

33     scanf("%d",&ca);

34     while( ca-- ){

35         people police,thief;

36         point new_one,new_two;

37         scanf("%lf%lf%lf%lf%lf",&thief.hi,&thief.r,&thief.x,&thief.y,&thief.z);

38         scanf("%lf%lf%lf%lf%lf%lf%lf%lf",&police.hi,&police.r,&police.x,&police.y,&police.z,&new_two.x,&new_two.y,&new_two.z);

39         

40         thief.z = thief.z+thief.hi-thief.r ;

41         police.z = police.z+0.9*police.hi-police.r ;

42         new_one.x = thief.x - police.x;

43         new_one.y = thief.y - police.y;

44         new_one.z = thief.z - police.z;//警察与小偷之间的向量

45         double tmp0,tmp1,tmp2;

46         tmp0=new_one.y*new_two.z-new_one.z*new_two.y;

47         tmp1=-new_one.x*new_two.z+new_one.z*new_two.x;

48         tmp2=new_one.x*new_two.y-new_one.y*new_two.x;

49         double sum;

50         sum = sqrt( fpow(tmp0)+fpow(tmp1)+fpow(tmp2) );

51         double ans;

52         ans = sum/sqrt(fpow(new_two.x)+fpow(new_two.y)+fpow(new_two.x));

53         //printf("%lf %lf\n",ans,thief.r);

54         if( ans<=thief.r && (new_one.x*new_two.x+new_one.y*new_two.y+new_one.z*new_two.z)>0 )

55             printf("YES\n");

56         else

57             printf("NO\n");

58     }

59     return 0;

60 }