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  1. #include <bits/stdc++.h> 
  2.  
  3. using namespace std;  
  4.  
  5. typedef long long ll;  
  6. typedef pair<int, int> ii;  
  7.  
  8. const int INF = 1e9;  
  9. const ll LINF = 1e18;  
  10.  
  11. const int N = 3e3 + 5; 
  12.  
  13. int n, m, k;  
  14. vector<int> adj[N]; 
  15. set<tuple<int, int, int>> ban;   
  16.  
  17. bool vis[N][N]; 
  18. int p[N][N];  
  19.  
  20. int bfs(int prv_s, int s) {
  21. 	memset(vis, false, sizeof vis);  
  22. 	memset(p, 0, sizeof p);  
  23.  
  24. 	queue<ii> q; 
  25. 	vis[prv_s][s] = true;
  26. 	p[prv_s][s] = 0;  
  27. 	q.push({prv_s, s}); 
  28.  
  29. 	while (!q.empty()) {
  30. 		ii front = q.front(); q.pop();  
  31. 		int prv_u = front.first, u = front.second; 
  32.  
  33. 		if (u == n) return prv_u; 
  34.  
  35. 		for (int nxt_u : adj[u]) {
  36. 			if (ban.count(make_tuple(prv_u, u, nxt_u))) continue; 
  37. 			if (!vis[u][nxt_u]) {
  38. 				vis[u][nxt_u] = true;  
  39. 				p[u][nxt_u] = prv_u;  
  40. 				q.push({u, nxt_u}); 
  41. 			}
  42. 		}
  43. 	}
  44.  
  45. 	return -1; 
  46. }
  47.  
  48. int main() {
  49. 	ios::sync_with_stdio(false); 
  50. 	cin.tie(nullptr); 	
  51. 	cin >> n >> m >> k; 
  52.  
  53. 	for (int i = 0; i < m; i++) {
  54. 		int u, v; 
  55. 		cin >> u >> v; 
  56. 		adj[u].push_back(v); 
  57. 		adj[v].push_back(u);
  58. 	}
  59.  
  60. 	for (int i = 0; i < k; i++) {
  61. 		int a, b, c; 
  62. 		cin >> a >> b >> c; 
  63. 		ban.insert(make_tuple(a, b, c));  
  64. 	}
  65.  
  66. 	int prv = bfs(0, 1);
  67. 	int cur = n;  
  68.  
  69. 	if (prv == -1) {
  70. 		cout << -1 << '\n'; 
  71. 		return 0; 
  72. 	}
  73.  
  74. 	vector<int> path;  
  75. 	while (true) {
  76. 		path.push_back(cur);  
  77. 		if (cur == 1) break; 
  78. 		int new_prv = p[prv][cur]; 
  79. 		cur = prv;  
  80. 		prv = new_prv; 
  81. 	}
  82.  
  83. 	reverse(path.begin(), path.end()); 
  84.  
  85. 	cout << path.size() - 1 << '\n'; 
  86. 	for (int u : path) cout << u << ' '; 
  87. }
Success #stdin #stdout 0.01s 47816KB
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https://ideone.com/iqS3Uj
language:
C++14 (gcc 8.3)
created:
291 days ago
visibility:
secret

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