1 #include<stdio.h>
2 #include<math.h>
3 #define MAXN 102
4 struct pos{
5 int x,y;
6 };
7 struct pos p[MAXN];
8 int n,d,flag;
9 int g[MAXN][MAXN],vis[MAXN];
10 double dis(struct pos p1,struct pos p2);
11 void read();
12 void creatg();
13 void dfs(int x);
14 int main(){
15 flag=0;
16 read();
17 creatg();
18 dfs(0);
19 if(flag==1) printf("Yes\n");
20 else printf("No\n");
21 return 0;
22 }
23 void read(){
24 int i;
25 scanf("%d %d",&n,&d);
26 for(i=1;i<=n;i++) scanf("%d %d",&p[i].x,&p[i].y);
27 for(i=0;i<=n+1;i++) vis[i] = 0;
28 }
29 double dis(struct pos p1,struct pos p2){
30 double t1 = pow((p1.x-p2.x),2) + pow((p1.y-p2.y),2);
31 return sqrt(t1);
32 }
33 void creatg(){
34 int i,j;
35 struct pos o;
36 o.x = 0;
37 o.y = 0;
38 for(i=0;i<=n+1;i++)
39 for(j=0;j<=n+1;j++)
40 g[i][j] = 0;
41
42 for(i=1;i<=n;i++){
43 if((dis(o,p[i])-15/2.0)<=d){
44 //if((dis(o,p[i]))<=d){
45 g[0][i] = 1;
46 g[i][0] = 1;
47 }
48 else {
49 g[0][i]=0;
50 g[i][0]=0;
51 }
52
53 if((50-abs(p[i].x))<=d || ((50-abs(p[i].y))<=d)) {
54 //可达
55 g[n+1][i] = 1;
56 g[i][n+1] = 1;
57 }
58 else{
59 g[n+1][i]=0;
60 g[i][n+1]=0;
61 }
62 }
63 for(i=1;i<=n;i++){
64 for(j=1;j<=n;j++){
65 if(i==j){
66 g[i][j] = 0;
67 g[j][i] = 0;
68 }
69 else{
70 if(dis(p[i],p[j])<=d){
71 g[i][j] = 1;
72 g[j][i] = 1;
73 }
74 else {
75 g[i][j] = 0;
76 g[j][i] = 0;
77 }
78 }
79 }
80 }
81
82
83 }
84 void dfs(int x){
85 vis[x] = 1;
86 //printf("%d\n",x);
87 if(x==n+1) flag=1;
88 int i;
89 for(i=1;i<=n+1;i++){
90 if(i!=x&&vis[i]==0&&g[x][i]!=0) dfs(i);
91 }
92 }
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