数据太大，heap优化是必须的，然后不能用vector建图，即必须静态建图，因为数据太大动态建图会超时（有的提示RE），最后就是正反建图Dijkstra了，顺便一提SPFA又快又好写。。。。。。

#include <cstdio>
#include <vector>
#include <queue>
using namespace std;
typedef long long ll;
const int INF = 0x3f3f3f3f;
const int maxn = 1e6 + 10;
int T, n, m, tot, head[2][maxn];
ll dis[maxn];
struct Node {
    int u, dis;
    Node(int x, int y) :u(x), dis(y) {}
    bool operator < (const Node &node) const {
        return node.dis < dis;
    }
};

struct Edge {
    int to, cost, next;
}edge[2][maxn];

void init() {
    tot = 0;
    for (int i = 1; i <= n; i++) head[0][i] = head[1][i] = -1;
}

void addedge(int flag, int u, int v, int cost) {
    edge[flag][tot].to = v;
    edge[flag][tot].cost = cost;
    edge[flag][tot].next = head[flag][u];
    head[flag][u] = tot;
}

ll dijkstra(int flag) {
    for (int i = 1; i <= n; i++) dis[i] = INF;
    dis[1] = 0;
    priority_queue<Node> q; q.push(Node(1, 0));
    while (!q.empty()) {
        Node node = q.top(); q.pop();
        int u = node.u;
        if (dis[u] < node.dis) continue;
        for (int i = head[flag][u]; i != -1; i = edge[flag][i].next) {
            int v = edge[flag][i].to, cost = edge[flag][i].cost;
            if (dis[v] > dis[u] + cost) {
                dis[v] = dis[u] + cost;
                q.push(Node(v, dis[v]));
            }
        }
    }
    ll ans = 0;
    for (int i = 1; i <= n; i++) {
        ans += dis[i];
    }
    return ans;
}

int main() {
    scanf("%d", &T);
    while (T--) {
        scanf("%d %d", &n, &m);
        init();
        for (int i = 1; i <= m; i++) {
            int u, v, cost; scanf("%d %d %d", &u, &v, &cost);
            ++tot;
            addedge(0, u, v, cost);
            addedge(1, v, u, cost);
        }
        ll ans = dijkstra(0) + dijkstra(1);
        printf("%I64d\n", ans);
    }
    return 0;
}