1 #include<cstdio> 2 #include<vector> 3 #include<cstring> 4 using namespace std; 5  6 const int maxn = 3000+10; 7  8 struct TwoSAT 9 {10     int n;11     vector<int> G[maxn*2];12     bool mark[maxn*2];13     int S[maxn*2], c;14 15     bool dfs(int x)16     {17         if (mark[x^1]) return false;18         if (mark[x]) return true;19         mark[x] = true;20         S[c++] = x;21         for (int i = 0; i < G[x].size(); i++)22             if (!dfs(G[x][i])) return false;23         return true;24     }25 26     void init(int n)27     {28         this->n = n;29         for (int i = 0; i < n*2; i++) G[i].clear();30         memset(mark, 0, sizeof(mark));31     }32 33     // x = xval or y = yval34     void add_clause(int x, int xval, int y, int yval)35     {36         x = x * 2 + xval;37         y = y * 2 + yval;38         G[x^1].push_back(y);39         G[y^1].push_back(x);40     }41 42     bool solve()43     {44         for(int i = 0; i < n*2; i += 2)45             if(!mark[i] && !mark[i+1])46             {47                 c = 0;48                 if(!dfs(i))49                 {50                     while(c > 0) mark[S[--c]] = false;51                     if(!dfs(i+1)) return false;52                 }53             }54         return true;55     }56 };57 58 59 ///////////////////////////////////////////////////////////////60 #include <iostream>61 #include <cmath>62 using namespace std;63 TwoSAT solver;64 65 int main()66 {67     int t,m;68     while(~scanf("%d%d",&t,&m))69     {70         solver.init(t*3);71         for(int i=0;i<t;i++)72         {73             int a,b,c;74             scanf("%d%d%d",&a,&b,&c);75             solver.add_clause(a,0,b,0); // 0表示不留下，1表示留下76             solver.add_clause(a,0,c,0);77             //solver.add_clause(b,1,c,0);78             //solver.add_clause(c,1,b,0);79         }80 81         for(int i=0;i<m;i++)82         {83             int a,b;84             scanf("%d %d",&a,&b);85             solver.add_clause(a,1,b,1);86         }87         printf("%s\n",solver.solve()?"yes":"no");88     }89     return 0;90 }