RT

#include <iostream>
#include <algorithm>
using namespace std;

struct Edge
{
    int u, v, w;
};

int a, b;
Edge e[25004];
int cnt;
int fa[502];
int kcnt;
int ans;

bool cmp(Edge x, Edge y)
{
    return x.w < y.w;
}

int find(int x)
{
    while(x != fa[x]) x = fa[x] = fa[fa[x]];
    return x;
}

void kruscal()
{
    sort(e + 1, e + 1 + cnt, cmp);
    for(int i = 1; i <= cnt; i++)
    {
        int fu = find(e[i].u);
        int fv = find(e[i].v);
        if(fu == fv)
        {
            continue;
        }
        ans += e[i].w;
        fa[fv] = fu;
    }
    return;
}

int main()
{
    cin >> a >> b;
    for(int i = 1; i <= b; i++)
    {
        for(int j = 1; j <= b; j++)
        {
            int k;
            cin >> k;
            if(k != 0)
            {
                cnt++;
                e[cnt].u = i;
                e[cnt].v = j;
                e[cnt].w = k;
            }
        }
    }
    for(int i = 1; i <= b; i++)
    {
        fa[i] = i;
        cnt++;
        e[cnt].u = 0;
        e[cnt].v = i;
        e[cnt].w = a;
    }
    kruscal();
    cout << ans << endl;
    return 0;
}

WA on #10 #11 #12