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Submission #248377

# Submission time Handle Problem Language Result Execution time Memory
248377 2020-07-12T10:17:58 Z Berted Commuter Pass (JOI18_commuter_pass) C++14
100 / 100
 516 ms 44272 KB 
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <bitset>
#define ll long long
#define pii pair<ll, ll>
#define fst first
#define snd second
#define vi vector<ll>
#define vpi vector<pii>

using namespace std;

const ll MX = 1e18;

int n, m, s, t, u, v;
vpi adj[100001] = {};
vpi keepTrack[100001] = {};
vi par[100001] = {};
ll dst[2][100001], ret = MX, dst2[100001] = {};
bitset<100001> bt;

inline void solveSSSP(int s, bool b)
{
	priority_queue<pii, vector<pii>, greater<pii>> pq;
	for (int i = 0; i < n; i++) dst[b][i] = -1;
	pq.push({0, s});
	while (pq.size())
	{
		int u = pq.top().snd; ll c = pq.top().fst; pq.pop();
		if (dst[b][u] == -1)
		{
			// cout << "DIJKSTRA - " << b << " " << u << " " << c << "\n";
			dst[b][u] = c;
			for (pii v : adj[u]) pq.push({c + v.snd, v.fst});
		}
	}
}

inline void specialTrav(int s, int t)
{
	priority_queue<pii, vector<pii>, greater<pii>> pq;
	dst2[s] = 0;
	pq.push({0, s});
	while (pq.size())
	{
		int u = pq.top().snd; ll c = pq.top().fst; pq.pop();
		if (dst2[u] == c)
		{
			pii tp1 = {dst[0][u], dst[1][u]}, tp2 = tp1;
			keepTrack[u].push_back(tp1);
			for (pii &pos : keepTrack[u])
			{
				pos.fst = min(pos.fst, dst[0][u]); pos.snd = min(pos.snd, dst[1][u]);
				if (pos < tp1) tp1 = pos;
				if (make_pair(pos.snd, pos.fst) < make_pair(tp2.snd, tp2.fst)) tp2 = pos;
			}
			if (u == t) break;
			for (pii v : adj[u])
			{
				if (c + v.snd < dst2[v.fst]) 
				{
					par[v.fst].clear(); 
					keepTrack[v.fst].clear(); 
					dst2[v.fst] = c + v.snd; 
					pq.push({c + v.snd, v.fst});
				}
				if (c + v.snd == dst2[v.fst]) 
				{
					keepTrack[v.fst].push_back(tp1); 
					keepTrack[v.fst].push_back(tp2); 
					par[v.fst].push_back(u);
				}
			}
		}
	}
}

inline void bktrk(int t)
{
	for (int i = 0; i < n; i++) dst2[i] = -1;
	queue<int> q;
	q.push(t);
	while (q.size())
	{
		int u = q.front(); q.pop();
		for (auto v : keepTrack[u]) {ret = min(ret, v.fst + v.snd);}
		for (auto v : par[u])
		{
			if (!bt[v]) {bt[v] = 1; q.push(v);}
		}
	}
}

int main()
{
	ios :: sync_with_stdio(0); cin.tie(0); cout.tie(0);
	cin >> n >> m;
	cin >> s >> t >> u >> v; s--; t--; u--; v--;
	for (int i = 0; i < n; i++)
	{
		dst[0][i] = dst[1][i] = -1;
		dst2[i] = MX;
	}
	for (int i = 0; i < m; i++)
	{
		int a, b, c; cin >> a >> b >> c;
		adj[a - 1].push_back({b - 1, c});
		adj[b - 1].push_back({a - 1, c});
	}
	solveSSSP(u, 0);
	solveSSSP(v, 1);
	specialTrav(s, t);
	bktrk(t);
	/*
	for (int i = 0; i < n; i++)
	{
		cout << "Node " << i << ": \n";
		for (auto pos : keepTrack[i])
		{
			cout << pos.fst << ", " << pos.snd << "\n";
		}
	}
	*/

	cout << min(dst[0][v], ret) << "\n";
	return 0;
}

Subtask #1
16.0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 456 ms 35776 KB Output is correct
2 Correct 416 ms 33704 KB Output is correct
3 Correct 451 ms 35840 KB Output is correct
4 Correct 443 ms 36044 KB Output is correct
5 Correct 417 ms 33168 KB Output is correct
6 Correct 495 ms 34028 KB Output is correct
7 Correct 453 ms 34000 KB Output is correct
8 Correct 396 ms 33196 KB Output is correct
9 Correct 403 ms 31292 KB Output is correct
10 Correct 430 ms 34064 KB Output is correct
11 Correct 194 ms 25852 KB Output is correct
12 Correct 516 ms 36288 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 421 ms 32636 KB Output is correct
2 Correct 426 ms 33004 KB Output is correct
3 Correct 441 ms 31808 KB Output is correct
4 Correct 424 ms 32704 KB Output is correct
5 Correct 431 ms 33748 KB Output is correct
6 Correct 485 ms 35900 KB Output is correct
7 Correct 425 ms 33124 KB Output is correct
8 Correct 442 ms 32860 KB Output is correct
9 Correct 421 ms 33724 KB Output is correct
10 Correct 391 ms 32172 KB Output is correct
11 Correct 177 ms 27768 KB Output is correct
12 Correct 469 ms 35968 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 27 ms 9920 KB Output is correct
2 Correct 4 ms 7424 KB Output is correct
3 Correct 5 ms 7424 KB Output is correct
4 Correct 58 ms 12616 KB Output is correct
5 Correct 29 ms 10844 KB Output is correct
6 Correct 6 ms 7552 KB Output is correct
7 Correct 7 ms 7680 KB Output is correct
8 Correct 8 ms 7680 KB Output is correct
9 Correct 6 ms 7552 KB Output is correct
10 Correct 28 ms 10708 KB Output is correct
11 Correct 4 ms 7424 KB Output is correct
12 Correct 6 ms 7424 KB Output is correct
13 Correct 5 ms 7424 KB Output is correct
14 Correct 6 ms 7564 KB Output is correct
15 Correct 5 ms 7552 KB Output is correct

Subtask #4
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 456 ms 35776 KB Output is correct
2 Correct 416 ms 33704 KB Output is correct
3 Correct 451 ms 35840 KB Output is correct
4 Correct 443 ms 36044 KB Output is correct
5 Correct 417 ms 33168 KB Output is correct
6 Correct 495 ms 34028 KB Output is correct
7 Correct 453 ms 34000 KB Output is correct
8 Correct 396 ms 33196 KB Output is correct
9 Correct 403 ms 31292 KB Output is correct
10 Correct 430 ms 34064 KB Output is correct
11 Correct 194 ms 25852 KB Output is correct
12 Correct 516 ms 36288 KB Output is correct
13 Correct 421 ms 32636 KB Output is correct
14 Correct 426 ms 33004 KB Output is correct
15 Correct 441 ms 31808 KB Output is correct
16 Correct 424 ms 32704 KB Output is correct
17 Correct 431 ms 33748 KB Output is correct
18 Correct 485 ms 35900 KB Output is correct
19 Correct 425 ms 33124 KB Output is correct
20 Correct 442 ms 32860 KB Output is correct
21 Correct 421 ms 33724 KB Output is correct
22 Correct 391 ms 32172 KB Output is correct
23 Correct 177 ms 27768 KB Output is correct
24 Correct 469 ms 35968 KB Output is correct
25 Correct 27 ms 9920 KB Output is correct
26 Correct 4 ms 7424 KB Output is correct
27 Correct 5 ms 7424 KB Output is correct
28 Correct 58 ms 12616 KB Output is correct
29 Correct 29 ms 10844 KB Output is correct
30 Correct 6 ms 7552 KB Output is correct
31 Correct 7 ms 7680 KB Output is correct
32 Correct 8 ms 7680 KB Output is correct
33 Correct 6 ms 7552 KB Output is correct
34 Correct 28 ms 10708 KB Output is correct
35 Correct 4 ms 7424 KB Output is correct
36 Correct 6 ms 7424 KB Output is correct
37 Correct 5 ms 7424 KB Output is correct
38 Correct 6 ms 7564 KB Output is correct
39 Correct 5 ms 7552 KB Output is correct
40 Correct 485 ms 39000 KB Output is correct
41 Correct 357 ms 31036 KB Output is correct
42 Correct 464 ms 36636 KB Output is correct
43 Correct 208 ms 27768 KB Output is correct
44 Correct 187 ms 27768 KB Output is correct
45 Correct 481 ms 40144 KB Output is correct
46 Correct 471 ms 39876 KB Output is correct
47 Correct 515 ms 41492 KB Output is correct
48 Correct 193 ms 27128 KB Output is correct
49 Correct 486 ms 44272 KB Output is correct
50 Correct 475 ms 40112 KB Output is correct
51 Correct 487 ms 40112 KB Output is correct