最小生成树

struct edge{
    int u,v,value;
    bool operator < (const edge &t){
        return value<t.value;
    }
}e[maxn];
int fath[maxn];
int find(int x){
    return x == fath[x] ? x : fath[x] = find(fath[x]);
}
int Kruskal(){
    int ans=0;
    for(int i = 1; i <= n; i++)fath[i] = i;
    sort(e+1,e+m+1);
    for(int i = 1; i <= m; i++){
        int fx = find(e[i].u);
        int fy = find(e[i].v);
        if(fx != fy){
            fath[fy] = fx;
            ans+=e[i].value;
        }
    }
    return ans;
}