RE求助 悬关

#include <bits/stdc++.h>
#define int long long
using namespace std;
const int N = 305;
int n, m, cnt, ans;
int a[N], b[N];
int arr[N][N], fa[N * N];
struct node {
    int x, y, w;
};
vector<node> Edge;
bool cmp(node x, node y) { return x.w < y.w; }
void init() {
    for (int i = 1; i <= n * m; i++) fa[i] = i;
}
int find(int x) {
    if(fa[x] == x) return x;
    else return fa[x] = find(fa[x]);
}
bool merge(int x, int y) {
    int Fx = find(x);
    int Fy = find(y);
    if(Fx == Fy) return false;
    fa[Fx] = Fy;
    return true;
}
signed main() {
    scanf("%lld%lld", &n, &m);
    init();
    for (int i = 1; i <= n; i++) scanf("%lld", a + i);
    for (int i = 1; i <= m; i++) scanf("%lld", b + i);
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            arr[i][j] = (i - 1) * n + j;
        }
    }
    for (int i = 1; i <= n; i++)
        for (int j = 1; j < m; j++)
            Edge.push_back({ arr[i][j], arr[i][j + 1], a[i] });
    for (int i = 1; i < n; i++)
        for (int j = 1; j <= m; j++)
            Edge.push_back({ arr[i][j], arr[i + 1][j], b[j] });
    sort(Edge.begin(), Edge.end(), cmp);
    for (node i : Edge) {
        if(cnt == n * m - 1) break;
        if(merge(i.x, i.y)) cnt++, ans += i.w;
    }
    printf("%lld", ans);
}