1 #include<cstdio> 2 #include<algorithm> 3 #include<functional> 4 struct Edge { 5     int u,v,w; 6     bool operator >(const Edge &x) const { 7         return this->w>x.w; 8     } 9 };10 const int N=20001;11 class UnionFindSet {12     private:13         int anc[N<<1];14         int Find(int x) {15             return (x==anc[x])?x:(anc[x]=Find(anc[x]));16         }17     public:18         UnionFindSet(const int n) {19             for(int i=1;i<=n<<1;i++) anc[i]=i;20         }21         bool isConnected(const int x,const int y) {22             return Find(x)==Find(y);23         }24         void Union(const int x,const int y) {25             anc[Find(x)]=Find(y);26         }27 };28 int main() {29     int n,m;30     scanf("%d%d",&n,&m);31     Edge e[m];32     for(int i=0;i<m;i++) {33         scanf("%d%d%d",&e[i].u,&e[i].v,&e[i].w);34     }35     std::sort(&e[0],&e[m],std::greater<Edge>());36     UnionFindSet s(n);37     for(int i=0;i<m;i++) {38         if(s.isConnected(e[i].u,e[i].v)) {39             printf("%d\n",e[i].w);40             return 0;41         }42         s.Union(e[i].u,e[i].v+n);43         s.Union(e[i].v,e[i].u+n);44     }45     puts("0");46     return 0;47 }