最小生成树kruskal算法

#include<cstdio>#include<cstring>#include<algorithm>using namespace std;int n,m,sum,tol;int fth[10000];struct node{    int f;    int t;    int v;} edge[100];int cmp(node a,node b){    return a.v<b.v;}int find(int x){    if(fth[x]==x)        return fth[x];    return fth[x]=find(fth[x]);}int kruskal(){    sum=0;    tol=0;    for(int i=1; i<=m; i++)    {        int f=edge[i].f;        int t=edge[i].t;        if(find(f)!=find(t))        {            fth[find(f)]=find(t);            sum+=edge[i].v;            tol++;        }        if(tol==n-1)            return sum;    }    return -1;}int main(){    while(~scanf("%d%d",&n,&m))    {        for(int i=1; i<=n; i++)        {            fth[i]=i;        }        for(int i=1; i<=m; i++)        {            scanf("%d%d%d",&edge[i].f,&edge[i].t,&edge[i].v);        }        sort(edge+1,edge+m+1,cmp);        int ans=kruskal();        printf("%d\n",ans);    }    return 0;}