#include <bits/stdc++.h> using namespace std; #define task "main" #define F first #define S second #define ii pair<int, int> #define il pair<int, long long> #define li pair<long long, int> #define FOR(i, a, b) for(int i = (a); i <= (b); ++i) #define FOD(i, b, a) for(int i = (b); i >= (a); --i) template <class T1, class T2> bool maximize(T1 &a, T2 b){ if (a < b) {a = b; return true;} return false; } template <class T1, class T2> bool minimize(T1 &a, T2 b){ if (a > b) {a = b; return true;} return false; } template <class T> void printArr(T container, string separator = " ", string finish = "\n", ostream &out = cout){ for(auto item: container) out << item << separator; out << finish; } const int MAX_N = (int)2e5 + 5; const long long INF = (long long)1e18 + 1408; int nNode, nEdge, s, t, l; long long k; vector<ii> adj[MAX_N]; long long dist[2][MAX_N]; priority_queue<li, vector<li>, greater<li>> pq; void dijkstra(int s, long long dist[]) { FOR(i, 1, nNode) dist[i] = INF; dist[s] = 0; pq.push({0, s}); while (!pq.empty()) { li cur = pq.top(); pq.pop(); int u = cur.S; if (cur.F > dist[u]) continue; for (ii e : adj[u]) { int v = e.F, w = e.S; if (minimize(dist[v], dist[u] + w)) pq.push({dist[v], v}); } } } void solve() { cin >> nNode >> nEdge; cin >> s >> t >> l >> k; FOR(i, 1, nEdge) { int u, v, w; cin >> u >> v >> w; adj[u].push_back({v, w}); adj[v].push_back({u, w}); } dijkstra(s, dist[0]); dijkstra(t, dist[1]); if (dist[0][t] <= k) { cout << 1LL * nNode * (nNode - 1) / 2; return; } sort(dist[0] + 1, dist[0] + nNode + 1); sort(dist[1] + 1, dist[1] + nNode + 1); long long ans = 0; FOR(i, 1, nNode) { if (k - l < dist[0][i]) break; int pos = upper_bound(dist[1] + 1, dist[1] + nNode + 1, k - l - dist[0][i]) - dist[1]; ans += pos - 1; } cout << ans; } int32_t main() { if (fopen(task".inp", "r")) { freopen(task".inp", "r", stdin); freopen(task".out", "w", stdout); } ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); bool multitest = 0; int numTest = 1; if (multitest) cin >> numTest; while (numTest--) { solve(); } return 0; } /* Lak lu theo dieu nhac!!!! */

Main.cpp: In function 'int32_t main()':
Main.cpp:92:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   92 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:93:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   93 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~