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Submission #209312

# Submission time Handle Problem Language Result Execution time Memory
209312 2020-03-13T16:53:39 Z AQT Olympic Bus (JOI20_ho_t4) C++14
21 / 100
 30 ms 2296 KB 
#include <bits/stdc++.h>

using namespace std;

int N, M;
vector<int> graph[205]; 
vector<int> rgraph[205];
int u[50005], v[50005], p[2][50005];
bool used[50005];
long long dist[2][205], cst[50005], rev[50005], rdist[2][205];
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;

void dijkstra(int s, int t){
	for(int i = 1; i<=N; i++){
		dist[t][i] = LLONG_MAX>>4;
	}
	dist[t][s] = 0;
	pq.push({0, s});
	while(pq.size()){
		auto pii = pq.top();
		pq.pop();
		if(dist[t][pii.second] != pii.first){
			continue;
		}
		int n = pii.second;
		for(int e : graph[n]){
			if(u[e] == n && dist[t][v[e]] > dist[t][u[e]] + cst[e]){
				dist[t][v[e]] = dist[t][u[e]] + cst[e];
				p[t][v[e]] = e;
				pq.push({dist[t][v[e]], v[e]});
			}
		}
	}
}

void rdijkstra(int s, int t){
	for(int i = 1; i<=N; i++){
		rdist[t][i] = LLONG_MAX>>4;
	}
	rdist[t][s] = 0;
	pq.push({0, s});
	while(pq.size()){
		auto pii = pq.top();
		pq.pop();
		if(rdist[t][pii.second] != pii.first){
			continue;
		}
		int n = pii.second;
		for(int e : rgraph[n]){
			if(rdist[t][u[e]] > rdist[t][v[e]] + cst[e]){
				rdist[t][u[e]] = rdist[t][v[e]] + cst[e];
				//p[t][u[e]] = u[e];
				pq.push({rdist[t][u[e]], u[e]});
			}
		}
	}
}

int main(){
	cin.sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin >> N >> M;
	for(int i = 1; i<=M; i++){
		cin >> u[i] >> v[i] >> cst[i] >> rev[i];
		graph[u[i]].push_back(i);
		rgraph[v[i]].push_back(i);
	}
	dijkstra(1, 0);
	dijkstra(N, 1);
	rdijkstra(1, 0);
	rdijkstra(N, 1);
	long long ans = dist[0][N] + dist[1][1];
	int crnt = N;
	while(p[0][crnt] && crnt != 1){
		used[p[0][crnt]] = 1;
		crnt = u[p[0][crnt]];
	}
	crnt = 1;
	while(p[1][crnt] && crnt != N){
		used[p[1][crnt]] = 1;
		crnt = u[p[1][crnt]];
	}
	for(int e = 1; e<=M; e++){
		if(!used[e]){
			ans = min(ans, dist[0][N] + dist[1][v[e]] + rdist[0][u[e]] + cst[e] + rev[e]);
			ans = min(ans, dist[1][1] + dist[0][v[e]] + rdist[1][u[e]] + cst[e] + rev[e]);
			ans = min(ans, dist[0][v[e]] + dist[1][v[e]] + rdist[0][u[e]] + rdist[1][u[e]] + rev[e]);		
		}
	}
	for(int e = 1; e<=M; e++){
		if(used[e]){
			swap(u[e], v[e]);
			graph[u[e]].push_back(e);
			dijkstra(1, 0);
			dijkstra(N, 1);
			graph[u[e]].pop_back();
			swap(u[e], v[e]);
			ans = min(ans, dist[0][N] + dist[1][1] + rev[e]);
		}
	}
	if(ans >= LLONG_MAX>>4){
		ans = -1;
	}
	cout << ans;
}

Subtask #1
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 508 KB Output is correct
2 Correct 5 ms 380 KB Output is correct
3 Correct 6 ms 376 KB Output is correct
4 Correct 6 ms 376 KB Output is correct
5 Incorrect 5 ms 376 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #2
0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 30 ms 2168 KB Output is correct
2 Incorrect 30 ms 2280 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #3
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 504 KB Output is correct
2 Correct 5 ms 376 KB Output is correct
3 Correct 23 ms 1784 KB Output is correct
4 Correct 5 ms 376 KB Output is correct
5 Correct 25 ms 2168 KB Output is correct
6 Correct 5 ms 504 KB Output is correct
7 Correct 5 ms 376 KB Output is correct
8 Correct 25 ms 2168 KB Output is correct
9 Correct 25 ms 2168 KB Output is correct
10 Correct 25 ms 2168 KB Output is correct
11 Correct 27 ms 2168 KB Output is correct
12 Correct 25 ms 2168 KB Output is correct
13 Correct 6 ms 376 KB Output is correct
14 Correct 5 ms 376 KB Output is correct
15 Correct 5 ms 376 KB Output is correct
16 Correct 5 ms 376 KB Output is correct
17 Correct 5 ms 376 KB Output is correct
18 Correct 5 ms 376 KB Output is correct
19 Correct 26 ms 2168 KB Output is correct
20 Correct 24 ms 2168 KB Output is correct
21 Correct 29 ms 2296 KB Output is correct
22 Correct 25 ms 2168 KB Output is correct

Subtask #4
0 / 63.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 508 KB Output is correct
2 Correct 5 ms 380 KB Output is correct
3 Correct 6 ms 376 KB Output is correct
4 Correct 6 ms 376 KB Output is correct
5 Incorrect 5 ms 376 KB Output isn't correct
6 Halted 0 ms 0 KB -