kruskal --- c++ (2)

#include <cstdio>
#include <algorithm>

using namespace std;

struct aaa{
    int l,r,w;
    bool operator < (const aaa& b) const {
        return w<b.w;
    }
}a[];
int fa[];

int find(int a)
{
    if (a != fa[a])
        return find(fa[a]);
    return a;
}

int main()
{
    int n,num = ,t;
    scanf("%d%d",&n,&t);
    for (int i = ; i<t; i++)
    {
        int x,y,z;
        scanf("%d%d%d",&x,&y,&z);
        a[num].l = x;
        a[num].r = y;
        a[num].w = z;
        num++;
    }

    sort(a,a+num);
    for (int i = ; i<n; i++)
        fa[i] = i;

    int nn = ,k = ;
    long long ans = ;
    while(nn<n-)
    {
        int faa = find(a[k].l),fab = find(a[k].r);
        if (faa != fab)
        {
            fa[a[k].l] = fab;
            fa[faa] = fab;

            nn++;
            ans += a[k].w;
        }
        k++;
    }

    printf("%lld",ans);
}

其实发上来意义也不大，只是输入不一样罢了。

题目来源：code[VS]