【2016ACM/ICPC亚洲区沈阳站A】HDU - 5971 Wrestling Match 二分图染色

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 const int MAX_N=1005;
 4 int n,color[MAX_N];
 5 vector<int> G[MAX_N];
 6 bool dfs(int v,int c)
 7 {
 8     color[v]=c;
 9     for(unsigned i=0;i<G[v].size();++i)
10     {
11         if(color[G[v][i]]==c)
12             return false;
13         if(color[G[v][i]]==0&&!dfs(G[v][i],-c))
14             return false;
15     }
16     return true;
17 }
18 void solve()
19 {
20     for(int i=1;i<=n;++i)
21         if(color[i]==-1)
22         {
23             cout<<"NO\n";
24             return;
25         }
26     for(int i=1;i<=n;++i)
27     {
28         if(color[i]==2&& !dfs(i,2))
29         {
30             cout<<"NO\n";
31             return;
32         }
33         if(color[i]==-2&& !dfs(i,-2))
34         {
35             cout<<"NO\n";
36             return;
37         }
38     }
39     for(int i=1;i<=n;++i)
40         if(color[i]==0)
41         {
42             if(!dfs(i,2))
43             {
44                 cout<<"NO\n";
45                 return;
46             }
47         }
48     cout<<"YES\n";
49 }
50 int main()
51 {
52     ios::sync_with_stdio(false);
53     int m,x,y;
54     while(cin>>n>>m>>x>>y)
55     {
56         int a,b;
57 
58         for(int i=1;i<=n;++i)//清空数据
59             G[i].clear();
60         memset(color,-1,sizeof(color));
61 
62         for(int i=1;i<=m;++i)
63         {
64             cin>>a>>b;
65             color[a]=0;
66             color[b]=0;
67             G[a].push_back(b);
68             G[b].push_back(a);
69         }
70         for(int i=1;i<=x;++i)
71         {
72             cin>>a;
73             color[a]=2;
74         }
75         for(int i=1;i<=y;++i)
76         {
77             cin>>b;
78             color[b]=-2;
79         }
80         solve();
81     }
82     return 0;
83 }