POJ 1511

#include<iostream>

#include<string>

#include<cstdio>

#include<cstring>

#include<cstdlib>

#include<algorithm>

#include<cmath>

#include<vector>

#include<map>

#define MAXN 1000005

#define MAXM 10005

#define MOD 10000

#define inf 1500000000

#define eps 1e-9

#define pi acos(-1.0)

typedef long long LL;

using namespace std;

int t, p, q, dis[MAXN], rdis[MAXN], u, v, w;

struct Edge {

int v, w, next;

} edge[MAXN], redge[MAXN];

int head[MAXN], rhead[MAXN], es, res, Q[MAXN];

bool vis[MAXN];

void init() {

memset(head, -1, sizeof(head));

memset(rhead, -1, sizeof(rhead));

res = es = 0;

}

void add(Edge *edge, int *head, int u, int v, int w, int &es) {

edge[es].v = v, edge[es].w = w, edge[es].next = head[u], head[u] = es++;

}

void spfa(Edge *edge, int *head, int dis[]) { 

for (int i = 1; i <= p; i++) 

dis[i] = inf;

dis[1] = 0;

memset(vis, false, sizeof(vis)); vis[1] = true;

int front, rear, u, v, w;

front = rear = 0;

Q[rear++] = 1;

while (front != rear) {

u = Q[front++]; front %= MAXN;

vis[u] = false;

for (int i = head[u]; i != -1; i = edge[i].next) {

v = edge[i].v, w = edge[i].w;

if (dis[u] + w < dis[v]) {

dis[v] = dis[u] + w;

if (!vis[v]) {

vis[v] = true;

Q[rear++] = v;

rear %= MAXN;

}

}

}

}

}

int main() {

//freopen("in.txt", "r", stdin);

//freopen("out.txt", "w", stdout);

scanf("%d", &t);

while (t--) {

init();

scanf("%d %d", &p, &q);

for (int i = 0; i < q; i++) {

scanf("%d %d %d", &u, &v, &w);

add(edge, head, u, v, w, es);

add(redge, rhead, v, u, w, res);

}

spfa(edge, head, dis);

spfa(redge, rhead, rdis);

LL ans = 0;

for (int i = 2; i <= p; i++) 

ans += dis[i] + rdis[i];

printf("%lld\n", ans);

}

    return 0;

}