Minimum spanning Tree 2 (Kruskal algorithm)

Kruskal algorithm:

1: In accordance with the weight of the edge of the order from small to large to see again, if you do not produce a circle (the heavy Edge also counted), the current edge is added to the spanning tree, the basic algorithm proved to be the same as prim

2: How to determine whether to create a negative circle, assuming now to join the vertex u and Vertex v of the edge e into the spanning tree, if you and V are not in the same Unicom component before joining, then the addition of e will not produce a negative circle, conversely, if you and V in the same connected component, then will be bound to produce a circle, You can use and check to see if it belongs to the same connected component.

The Ps:kruskal algorithm is time-consuming to sort the edges, and the algorithm complexity is O (| E|log| v|)

struct node{    int u,v,w;} edge[max_v*max_v];bool cmp (node A,node b) {    if (A.W<=B.W) return true;    return false;} int find (int x) {    if (X!=father[x]) return find (Father[x]);     return x;} int Kruskal (int n,int m) {    sort (edge,edge+m,cmp);    int x,y,res=0;    for (int i=0; i<m; i++)    {        x=edge[i].u;        Y=EDGE[I].V;        X=find (x);        Y=find (y);        if (x!=y)        {            res+=edge[i].w;            father[y]=x;        }    }    return res;}

Minimum spanning Tree 2 (Kruskal algorithm)