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Submission #207392

# Submission time Handle Problem Language Result Execution time Memory
207392 2020-03-07T13:11:32 Z Saboon Commuter Pass (JOI18_commuter_pass) C++14
100 / 100
 587 ms 27300 KB 
#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
 
const int maxn = 1e5 + 10;
const int inf = 1e9;
 
int n, m;
vector<pair<int,ll>> g[maxn];
vector<int> G[maxn];
ll dp[maxn], pd[maxn];

bool mark[maxn];
int Q[maxn], tail, head;
vector<int> builddag(int s, int t){
	tail = 0, head = 0;
	mark[t] = 1, Q[head ++] = t;
	vector<int> ret;
	while (tail < head){
		int v = Q[tail ++];
		ret.push_back(v);
		for (auto ed : g[v]){
			int u = ed.first, w = ed.second;
			if (!mark[u] and dp[u] + w == dp[v])
				mark[u] = 1, Q[head ++] = u;
			if (dp[u] + w == dp[v])
				G[v].push_back(u);
		}
	}
	sort(ret.begin(), ret.end(), [] (int v, int u){ return dp[v] < dp[u];} );
	return ret;
}

void dijkstra(int src){
	memset(dp, 63, sizeof dp);
	dp[src] = 0;
	set<pair<ll,int>> s;
	s.insert({dp[src], src});
	while (!s.empty()){
		int v = (*s.begin()).second;
		s.erase(s.begin());
		for (auto ed : g[v]){
			int u = ed.first, w = ed.second;
			if (dp[u] > dp[v] + w){
				s.erase({dp[u], u});
				dp[u] = dp[v] + w;
				s.insert({dp[u], u});
			}
		}
	}
}

ll dpfr[maxn], dpto[maxn];

int main(){
	ios_base::sync_with_stdio(false);
	int m;
	int s, t;
	int fr, to;
	cin >> n >> m >> s >> t >> fr >> to;
	for (int i = 0; i < m; i++){
		int v, u, c;
		cin >> v >> u >> c;
		g[v].push_back({u, c});
		g[u].push_back({v, c});
	}
	dijkstra(fr); // keep shortest path data in dp
	for (int i = 1; i <= n; i++)
		dpfr[i] = dp[i];
	dijkstra(to); // keep shortest path data in dp
	for (int i = 1; i <= n; i++)
		dpto[i] = dp[i];
	dijkstra(s); // keep shortest path data in dp
	ll answer = dpfr[to];
	vector<int> tpl = builddag(s, t); // topological sort of shortest path's DAG s to t 
	for (int i = 0; i < (int)tpl.size(); i++){
		int v = tpl[i];
		dp[v] = dpfr[v], pd[v] = dpto[v];
		for (auto u : G[v]){
			dp[v] = min(dp[v], dp[u]);
			pd[v] = min(pd[v], pd[u]);
		}
		ll now = min(dp[v] + dpto[v], pd[v] + dpfr[v]);
		if (answer == -1 or answer > now)
			answer = now;
	}
	cout << answer << '\n';
}

Subtask #1
16.0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 499 ms 20856 KB Output is correct
2 Correct 481 ms 19832 KB Output is correct
3 Correct 479 ms 20628 KB Output is correct
4 Correct 463 ms 20856 KB Output is correct
5 Correct 436 ms 19972 KB Output is correct
6 Correct 551 ms 20856 KB Output is correct
7 Correct 445 ms 20380 KB Output is correct
8 Correct 446 ms 23584 KB Output is correct
9 Correct 440 ms 24312 KB Output is correct
10 Correct 352 ms 24568 KB Output is correct
11 Correct 155 ms 16884 KB Output is correct
12 Correct 492 ms 24060 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 522 ms 20216 KB Output is correct
2 Correct 502 ms 19704 KB Output is correct
3 Correct 493 ms 19832 KB Output is correct
4 Correct 522 ms 19704 KB Output is correct
5 Correct 530 ms 19704 KB Output is correct
6 Correct 451 ms 20288 KB Output is correct
7 Correct 504 ms 20612 KB Output is correct
8 Correct 511 ms 19576 KB Output is correct
9 Correct 504 ms 19704 KB Output is correct
10 Correct 507 ms 19704 KB Output is correct
11 Correct 175 ms 15604 KB Output is correct
12 Correct 470 ms 20636 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 7160 KB Output is correct
2 Correct 9 ms 5880 KB Output is correct
3 Correct 9 ms 5880 KB Output is correct
4 Correct 26 ms 9208 KB Output is correct
5 Correct 18 ms 7672 KB Output is correct
6 Correct 9 ms 6008 KB Output is correct
7 Correct 10 ms 6008 KB Output is correct
8 Correct 10 ms 6008 KB Output is correct
9 Correct 9 ms 6008 KB Output is correct
10 Correct 18 ms 7544 KB Output is correct
11 Correct 8 ms 5880 KB Output is correct
12 Correct 9 ms 5880 KB Output is correct
13 Correct 9 ms 5880 KB Output is correct
14 Correct 9 ms 5880 KB Output is correct
15 Correct 9 ms 5880 KB Output is correct

Subtask #4
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 499 ms 20856 KB Output is correct
2 Correct 481 ms 19832 KB Output is correct
3 Correct 479 ms 20628 KB Output is correct
4 Correct 463 ms 20856 KB Output is correct
5 Correct 436 ms 19972 KB Output is correct
6 Correct 551 ms 20856 KB Output is correct
7 Correct 445 ms 20380 KB Output is correct
8 Correct 446 ms 23584 KB Output is correct
9 Correct 440 ms 24312 KB Output is correct
10 Correct 352 ms 24568 KB Output is correct
11 Correct 155 ms 16884 KB Output is correct
12 Correct 492 ms 24060 KB Output is correct
13 Correct 522 ms 20216 KB Output is correct
14 Correct 502 ms 19704 KB Output is correct
15 Correct 493 ms 19832 KB Output is correct
16 Correct 522 ms 19704 KB Output is correct
17 Correct 530 ms 19704 KB Output is correct
18 Correct 451 ms 20288 KB Output is correct
19 Correct 504 ms 20612 KB Output is correct
20 Correct 511 ms 19576 KB Output is correct
21 Correct 504 ms 19704 KB Output is correct
22 Correct 507 ms 19704 KB Output is correct
23 Correct 175 ms 15604 KB Output is correct
24 Correct 470 ms 20636 KB Output is correct
25 Correct 18 ms 7160 KB Output is correct
26 Correct 9 ms 5880 KB Output is correct
27 Correct 9 ms 5880 KB Output is correct
28 Correct 26 ms 9208 KB Output is correct
29 Correct 18 ms 7672 KB Output is correct
30 Correct 9 ms 6008 KB Output is correct
31 Correct 10 ms 6008 KB Output is correct
32 Correct 10 ms 6008 KB Output is correct
33 Correct 9 ms 6008 KB Output is correct
34 Correct 18 ms 7544 KB Output is correct
35 Correct 8 ms 5880 KB Output is correct
36 Correct 9 ms 5880 KB Output is correct
37 Correct 9 ms 5880 KB Output is correct
38 Correct 9 ms 5880 KB Output is correct
39 Correct 9 ms 5880 KB Output is correct
40 Correct 587 ms 27300 KB Output is correct
41 Correct 503 ms 24440 KB Output is correct
42 Correct 479 ms 24312 KB Output is correct
43 Correct 193 ms 19180 KB Output is correct
44 Correct 190 ms 19312 KB Output is correct
45 Correct 448 ms 25368 KB Output is correct
46 Correct 422 ms 25100 KB Output is correct
47 Correct 521 ms 24508 KB Output is correct
48 Correct 194 ms 18672 KB Output is correct
49 Correct 373 ms 26988 KB Output is correct
50 Correct 447 ms 24504 KB Output is correct
51 Correct 442 ms 25380 KB Output is correct