POJ 3463

#include <set>
#include <map>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <vector>
#include <bitset>
#include <string>
#include <cctype>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>
// #include <unordered_map>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<ull, ull> puu;

#define inf (0x3f3f3f3f)
#define lnf (0x3f3f3f3f3f3f3f3f)
#define eps (1e-9)
#define fi first
#define se second

bool sgn(double a, string select, double b) {
    if(select == "==")return fabs(a - b) < eps;
    if(select == "!=")return fabs(a - b) > eps;
    if(select == "<")return a - b < -eps;
    if(select == "<=")return a - b < eps;
    if(select == ">")return a - b > eps;
    if(select == ">=")return a - b > -eps;
}


//--------------------------

const ll mod = 1000000007;
const int maxn = 100010;

//use to bfs
struct Node {
    int v, c;
    int kind;
    Node(int _v = 0, int _c = 0, int _kind = 0) {
        v = _v, c = _c, kind = _kind;
    }
    bool operator<(const Node &a)const {
        return c > a.c;
    }
};

//first is 'v' , second is 'cost'
vector<pii> edge[maxn];
bool vis[maxn][2];
int dist[maxn][2];
int sav[maxn][2];

void addedge(int u, int v, int w) {
    edge[u].push_back(make_pair(v, w));
}



// id from 1
int  dijkstra_heap(int n, int start, int stop) {
    memset(vis, 0, sizeof(vis));
    memset(sav, 0, sizeof(sav));
    for(int i = 1; i <= n; i++) dist[i][0] = dist[i][1] = inf;
    priority_queue<Node> que;
    while(!que.empty())que.pop();
    dist[start][0] = 0;
    sav[start][0] = 1;
    que.push(Node(start, 0, 0));
    Node tmp;
    while(!que.empty()) {
        tmp = que.top();
        que.pop();
        int u = tmp.v;
        int kind = tmp.kind;
        if(vis[u][kind])continue;
        vis[u][kind] = true;
        for(int i = 0; i < edge[u].size(); i++) {
            int v = edge[u][i].fi;
            int cost = edge[u][i].se;
            if(dist[u][kind] + cost < dist[v][0]) {
                dist[v][1] = dist[v][0];
                sav[v][1] = sav[v][0];
                dist[v][0] = dist[u][kind] + cost;
                sav[v][0] = sav[u][kind];
                que.push(Node(v, dist[v][0], 0));
                que.push(Node(v, dist[v][1], 1));
            } else if(dist[u][kind] + cost == dist[v][0]) {
                sav[v][0] += sav[u][kind];
            } else if(dist[u][kind] + cost < dist[v][1]) {
                dist[v][1] = dist[u][kind] + cost;
                sav[v][1] = sav[u][kind];
                que.push(Node(v, dist[v][1], 1));
            } else if(dist[u][kind] + cost == dist[v][1]) {
                sav[v][1] += sav[u][kind];
            }
        }
    }
    if(dist[stop][0] + 1 == dist[stop][1])return sav[stop][0] + sav[stop][1];
    return sav[stop][0];
}

int s, t;
int n, m;


void solve() {
    int kase;
    scanf("%d", &kase);
    while(kase--) {
        for(int i = 1; i <= n; i++) {
            edge[i].clear();
        }
        scanf("%d%d", &n, &m);
        int u, v, w;
        for(int i = 0; i < m; i++) {
            scanf("%d%d%d", &u, &v, &w);
            addedge(u, v, w);
        }
        scanf("%d%d", &s, &t);
        int ans = dijkstra_heap(n, s, t);
        printf("%d\n", ans );
    }

}

int main() {

#ifndef ONLINE_JUDGE
    freopen("1.in", "r", stdin);
    freopen("1.out", "w", stdout);
#endif
    // iostream::sync_with_stdio(false);
    solve();
    return 0;
}