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緇嗚妭錛?You must assume that two floating point numbers a and b are equal if |a - b| < 10^-8.
鍗曟潯鐩寸嚎蹇?Yes
1
2#include<stdio.h>
3#include <stdlib.h>
4#include <math.h>
5#define N 101
6#define MAXN 1000
7#define offset 10000
8#define eps 1e-8
9#define zero(x) (((x)>0?(x):-(x))<eps)
10#define _sign(x) ((x)>eps?1:((x)<-eps?2:0))
11
struct point
{double x,y;};
12struct line{point a,b;};
13
14int n;
15line arr[N];
16
17double xmult(point p1,point p2,point p0){
18
return (p1.x-p0.x)*(p2.y-p0.y)-(p2.x-p0.x)*(p1.y-p0.y);
19
}
20int same_side(point p1,point p2,point l1,point l2){
21 return xmult(l1,p1,l2)*xmult(l1,p2,l2)>eps;
22}
23
24int IsConver(int i,int j,point a,point b){
25 int step;
26 for(step=0;step<n;step++)
27
if(step!=i&&step!=j){
28 if(same_side(arr[step].a,arr[step].b,a,b)) return 0;
29
}
30 return 1;
31}
32
33int Find(){
34 int i,j,flag;
35 flag=0;
36 for(i=0;i<n;i++)
37 for(j=0;j<n;j++){
38 if(i!=j){
39 flag=1;
40 if(
41 !zero(sqrt((arr[i].a.x-arr[j].a.x)*(arr[i].a.x-arr[j].a.x)+(arr[i].a.y-arr[j].a.y)*(arr[i].a.y-arr[j].a.y))) &&
42 IsConver(i,j,arr[i].a,arr[j].a)
43 )
44 return 1;
45
46 if(
47 !zero(sqrt((arr[i].b.x-arr[j].b.x)*(arr[i].b.x-arr[j].b.x)+(arr[i].b.y-arr[j].b.y)*(arr[i].b.y-arr[j].b.y))) &&
48 IsConver(i,j,arr[i].b,arr[j].b)
49 )
50 return 1;
51
52 if(
53 !zero(sqrt((arr[i].a.x-arr[j].b.x)*(arr[i].a.x-arr[j].b.x)+(arr[i].a.y-arr[j].b.y)*(arr[i].a.y-arr[j].b.y))) &&
54 IsConver(i,j,arr[i].a,arr[j].b)
55 )
56 return 1;
57
58 if(
59 !zero(sqrt( (arr[i].b.x-arr[j].a.x)*(arr[i].b.x-arr[j].a.x)+(arr[i].b.y-arr[j].a.y)*(arr[i].b.y-arr[j].a.y))) &&
60 IsConver(i,j,arr[i].b,arr[j].a)
61 )
62 return 1;
63
64 }
65 }
66 if(flag==0) return 1;
67 else return 0;
68}
69
70int main(){
71 int t,_case,i,j,step;
72 scanf("%d",&t);
73 for(_case=0;_case<t;_case++){
74 scanf("%d",&n);
75 for(i=0;i<n;i++)
76 scanf("%lf%lf%lf%lf",&arr[i].a.x,&arr[i].a.y,&arr[i].b.x,&arr[i].b.y);
77
78 if(Find()) printf("Yes!\n");
79 else printf("No!\n");
80 }
81 return 0;
82}
83
2
#include<stdio.h>3
#include <stdlib.h>4
#include <math.h>5
#define N 1016
#define MAXN 10007
#define offset 100008
#define eps 1e-89
#define zero(x) (((x)>0?(x):-(x))<eps)10
#define _sign(x) ((x)>eps?1:((x)<-eps?2:0))11
struct point{double x,y;};12
struct line{point a,b;};13
14
int n;15
line arr[N];16
17
double xmult(point p1,point p2,point p0){18
return (p1.x-p0.x)*(p2.y-p0.y)-(p2.x-p0.x)*(p1.y-p0.y);19
}20
int same_side(point p1,point p2,point l1,point l2){21
return xmult(l1,p1,l2)*xmult(l1,p2,l2)>eps;22
}23
24
int IsConver(int i,int j,point a,point b){25
int step;26
for(step=0;step<n;step++)27
if(step!=i&&step!=j){28
if(same_side(arr[step].a,arr[step].b,a,b)) return 0;29
}30
return 1;31
}32
33
int Find(){34
int i,j,flag;35
flag=0;36
for(i=0;i<n;i++)37
for(j=0;j<n;j++){38
if(i!=j){39
flag=1;40
if(41
!zero(sqrt((arr[i].a.x-arr[j].a.x)*(arr[i].a.x-arr[j].a.x)+(arr[i].a.y-arr[j].a.y)*(arr[i].a.y-arr[j].a.y))) &&42
IsConver(i,j,arr[i].a,arr[j].a)43
)44
return 1;45
46
if(47
!zero(sqrt((arr[i].b.x-arr[j].b.x)*(arr[i].b.x-arr[j].b.x)+(arr[i].b.y-arr[j].b.y)*(arr[i].b.y-arr[j].b.y))) &&48
IsConver(i,j,arr[i].b,arr[j].b)49
)50
return 1;51
52
if(53
!zero(sqrt((arr[i].a.x-arr[j].b.x)*(arr[i].a.x-arr[j].b.x)+(arr[i].a.y-arr[j].b.y)*(arr[i].a.y-arr[j].b.y))) &&54
IsConver(i,j,arr[i].a,arr[j].b)55
)56
return 1;57
58
if(59
!zero(sqrt( (arr[i].b.x-arr[j].a.x)*(arr[i].b.x-arr[j].a.x)+(arr[i].b.y-arr[j].a.y)*(arr[i].b.y-arr[j].a.y))) &&60
IsConver(i,j,arr[i].b,arr[j].a)61
)62
return 1;63
64
}65
}66
if(flag==0) return 1;67
else return 0;68
}69
70
int main(){71
int t,_case,i,j,step;72
scanf("%d",&t);73
for(_case=0;_case<t;_case++){74
scanf("%d",&n);75
for(i=0;i<n;i++)76
scanf("%lf%lf%lf%lf",&arr[i].a.x,&arr[i].a.y,&arr[i].b.x,&arr[i].b.y);77
78
if(Find()) printf("Yes!\n");79
else printf("No!\n");80
}81
return 0;82
}83
]]>