2
6 9
1 4
1 5
1 6
2 4
2 5
2 6
3 4
3 5
3 6
1 4 2 5 3 6
5 5
1 2
2 3
3 4
4 5
5 1
1 2 3 4 5

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<algorithm>
 5 #include<cmath>
 6 using namespace std;
 7 struct Node
 8 {
 9   int next,to;
10 }edge[100001];
11 struct Edge
12 {
13   int u,v;
14 }e[20001];
15 int head[1001],num,n,m,id[1001],cnt;
16 int vis[1001];
17 void add(int u,int v)
18 {
19   num++;
20   edge[num].next=head[u];
21   head[u]=num;
22   edge[num].to=v;
23 }
24 bool dfs(int x,int pa,int k)
25 {int i;
26   vis[x]=k^1;
27   for (i=head[x];i;i=edge[i].next)
28     {
29       int v=edge[i].to;
30       if (vis[v]==-1)
31     {
32       if (!dfs(v,x,k^1)) return 0;
33     }
34       else
35     {
36       if (vis[v]==(k^1))
37         return 0;
38     }
39     }
40   return 1;
41 }
42 int main()
43 {int T,i,j,x;
44   cin>>T;
45   while (T--)
46     {
47       cin>>n>>m;
48       for (i=1;i<=m;i++)
49     {
50       scanf("%d%d",&e[i].u,&e[i].v);
51     }
52       memset(id,0,sizeof(id));
53       for (i=1;i<=n;i++)
54     {
55       scanf("%d",&x);
56       id[x]=i;
57     }
58       if (m>3*n-6)
59     {
60       printf("NO\n");
61       continue;
62     }
63       num=0;
64       memset(head,0,sizeof(head));
65       for (i=1;i<=m;i++)
66     {
67       int u=e[i].u,v=e[i].v;
68       if (id[u]>id[v]) swap(u,v);
69       for (j=1;j<i;j++)
70         {
71           int p=e[j].u,q=e[j].v;
72           if (id[p]>id[q]) swap(p,q);
73           if (id[u]<id[p]&&id[v]<id[q]&&id[p]<id[v]) add(i,j),add(j,i);
74           if (id[p]<id[u]&&id[q]<id[v]&&id[u]<id[q]) add(i,j),add(j,i);
75         }
76     }
77       memset(vis,-1,sizeof(vis));
78       for (i=1;i<=m;i++)
79     if (vis[i]==-1)
80     {
81       if (!dfs(i,0,0)) break;
82     }
83       if (i>m) printf("YES\n");
84       else printf("NO\n");
85     }
86 }