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Submission #497132

# Submission time Handle Problem Language Result Execution time Memory
497132 2021-12-22T13:50:39 Z saarang123 Olympic Bus (JOI20_ho_t4) C++17
100 / 100
 204 ms 2884 KB 
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int mxn = 203;
const ll inf = 1e12;
vector<vector<ll>> adj, rev;
vector<vector<bool>> inpath;
vector<array<int, 2>> edges[mxn][mxn];
int n, m;

vector<int> dijkstra(int src, vector<ll> &dist, vector<vector<ll>> &g) {
	dist = vector<ll>(n, inf);
	dist[src] = 0;
	vector<int> p(n, -1);
	vector<bool> vis(n, false);
	while(true) {
		pair<ll, int> mn = {inf, -1};
		for(int i = 0; i < n; i++) if(!vis[i])
			mn = min(mn, {dist[i], i});

		if(mn.first >= inf)
			break;
		vis[mn.second] = true;
		for(int u = 0; u < n; u++) {
			if(g[mn.second][u] >= inf) continue;
			ll ndist = mn.first + g[mn.second][u];
			if(ndist < dist[u]) {
				dist[u] = ndist;
				p[u] = mn.second;
			}
		}
	}
	return p;
}

void extract(int end, vector<int> p) {
	vector<int> path;
	path.push_back(end);
	while(p[path.back()] > -1) 
		path.push_back(p[path.back()]);
	reverse(path.begin(), path.end());

	for(int i = 1; i < (int) path.size(); i++)
		inpath[path[i - 1]][path[i]] = true;
}

template<typename T>
void out(vector<T> a) {
	for(T x : a)
		cout << x << ' ';
	cout << endl;
}

signed main() {
    std::ios::sync_with_stdio(0);
    std::cout.tie(0);
    std::cin.tie(0);
    cin >> n >> m;
    adj = rev = vector<vector<ll>>(n, vector<ll>(n, inf));
    inpath = vector<vector<bool>>(n, vector<bool>(n, false));

    for(int u, v, c, d, i = 0; i < m; i++) {
    	cin >> u >> v >> c >> d;
    	u--, v--;
    	adj[u][v] = min(adj[u][v], (ll) c);
    	rev[v][u] = min(rev[v][u], (ll) c);
    	edges[u][v].push_back({c, d});
    }

    for(int i = 0; i < n; i++)
    	for(int j = 0; j < n; j++)
    		sort(edges[i][j].begin(), edges[i][j].end());

    vector<ll> d1, dn, r1, rn;
    extract(n - 1, dijkstra(0, d1, adj));
    extract(0, dijkstra(n - 1, dn, adj));
    dijkstra(0, r1, rev);
    dijkstra(n - 1, rn, rev);

    //out(d1); out(dn); out(r1); out(rn);

    ll ans = d1[n - 1] + dn[0];
    for(int u = 0; u < n; u++) {
    	for(int v = 0; v < n; v++) if(!edges[u][v].empty()) {
    		if(inpath[u][v]) {
    			ll uv = adj[u][v], vu = adj[v][u];
    			adj[u][v] = (edges[u][v].size() > 1 ? edges[u][v][1][0] : inf);
    			adj[v][u] = edges[u][v][0][0];

    			vector<ll> nd1, ndn;
    			dijkstra(0, nd1, adj);
    			dijkstra(n - 1, ndn, adj);
    			ll cost = nd1[n - 1] + ndn[0] + edges[u][v][0][1];
    			ans = min(ans, cost);

    			adj[u][v] = uv;
    			adj[v][u] = vu;
    		} 

    		for(int i = 0 + inpath[u][v]; i < (int) edges[u][v].size(); i++) {
    			auto [c, d] = edges[u][v][i];
    			ll c1 = d1[v] + rn[u] + c + d; //1 -> v -> u -> n
    			ll c2 = dn[v] + r1[u] + c + d; //n -> v -> u -> 1
    			ans = min({ans, c1 + dn[0], c2 + d1[n - 1], c1 + c2 - d});
    		}
    	}
    }

    cout << (ans >= inf ? -1 : ans) << '\n';
    return 0;
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 1868 KB Output is correct
2 Correct 1 ms 1868 KB Output is correct
3 Correct 5 ms 1868 KB Output is correct
4 Correct 8 ms 1868 KB Output is correct
5 Correct 1 ms 1228 KB Output is correct
6 Correct 2 ms 1868 KB Output is correct
7 Correct 1 ms 1228 KB Output is correct
8 Correct 1 ms 1228 KB Output is correct
9 Correct 1 ms 1228 KB Output is correct
10 Correct 69 ms 1868 KB Output is correct
11 Correct 88 ms 1988 KB Output is correct
12 Correct 82 ms 1868 KB Output is correct
13 Correct 2 ms 1868 KB Output is correct
14 Correct 5 ms 1868 KB Output is correct
15 Correct 4 ms 1896 KB Output is correct
16 Correct 4 ms 1984 KB Output is correct

Subtask #2
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 28 ms 2568 KB Output is correct
2 Correct 41 ms 2620 KB Output is correct
3 Correct 28 ms 2640 KB Output is correct
4 Correct 6 ms 1964 KB Output is correct
5 Correct 6 ms 1968 KB Output is correct
6 Correct 1 ms 1868 KB Output is correct
7 Correct 1 ms 1868 KB Output is correct
8 Correct 1 ms 1228 KB Output is correct
9 Correct 22 ms 2628 KB Output is correct
10 Correct 22 ms 2508 KB Output is correct
11 Correct 27 ms 2584 KB Output is correct
12 Correct 26 ms 2560 KB Output is correct
13 Correct 24 ms 2508 KB Output is correct
14 Correct 25 ms 2508 KB Output is correct

Subtask #3
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 1868 KB Output is correct
2 Correct 2 ms 1868 KB Output is correct
3 Correct 22 ms 2764 KB Output is correct
4 Correct 1 ms 1868 KB Output is correct
5 Correct 35 ms 2856 KB Output is correct
6 Correct 1 ms 1228 KB Output is correct
7 Correct 1 ms 1228 KB Output is correct
8 Correct 23 ms 2812 KB Output is correct
9 Correct 24 ms 2856 KB Output is correct
10 Correct 23 ms 2764 KB Output is correct
11 Correct 25 ms 2764 KB Output is correct
12 Correct 32 ms 2696 KB Output is correct
13 Correct 2 ms 1228 KB Output is correct
14 Correct 1 ms 1228 KB Output is correct
15 Correct 1 ms 1228 KB Output is correct
16 Correct 1 ms 1228 KB Output is correct
17 Correct 1 ms 1228 KB Output is correct
18 Correct 1 ms 1228 KB Output is correct
19 Correct 26 ms 2788 KB Output is correct
20 Correct 26 ms 2696 KB Output is correct
21 Correct 24 ms 2796 KB Output is correct
22 Correct 25 ms 2872 KB Output is correct

Subtask #4
63.0 / 63.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 1868 KB Output is correct
2 Correct 1 ms 1868 KB Output is correct
3 Correct 5 ms 1868 KB Output is correct
4 Correct 8 ms 1868 KB Output is correct
5 Correct 1 ms 1228 KB Output is correct
6 Correct 2 ms 1868 KB Output is correct
7 Correct 1 ms 1228 KB Output is correct
8 Correct 1 ms 1228 KB Output is correct
9 Correct 1 ms 1228 KB Output is correct
10 Correct 69 ms 1868 KB Output is correct
11 Correct 88 ms 1988 KB Output is correct
12 Correct 82 ms 1868 KB Output is correct
13 Correct 2 ms 1868 KB Output is correct
14 Correct 5 ms 1868 KB Output is correct
15 Correct 4 ms 1896 KB Output is correct
16 Correct 4 ms 1984 KB Output is correct
17 Correct 28 ms 2568 KB Output is correct
18 Correct 41 ms 2620 KB Output is correct
19 Correct 28 ms 2640 KB Output is correct
20 Correct 6 ms 1964 KB Output is correct
21 Correct 6 ms 1968 KB Output is correct
22 Correct 1 ms 1868 KB Output is correct
23 Correct 1 ms 1868 KB Output is correct
24 Correct 1 ms 1228 KB Output is correct
25 Correct 22 ms 2628 KB Output is correct
26 Correct 22 ms 2508 KB Output is correct
27 Correct 27 ms 2584 KB Output is correct
28 Correct 26 ms 2560 KB Output is correct
29 Correct 24 ms 2508 KB Output is correct
30 Correct 25 ms 2508 KB Output is correct
31 Correct 8 ms 1868 KB Output is correct
32 Correct 2 ms 1868 KB Output is correct
33 Correct 22 ms 2764 KB Output is correct
34 Correct 1 ms 1868 KB Output is correct
35 Correct 35 ms 2856 KB Output is correct
36 Correct 1 ms 1228 KB Output is correct
37 Correct 1 ms 1228 KB Output is correct
38 Correct 23 ms 2812 KB Output is correct
39 Correct 24 ms 2856 KB Output is correct
40 Correct 23 ms 2764 KB Output is correct
41 Correct 25 ms 2764 KB Output is correct
42 Correct 32 ms 2696 KB Output is correct
43 Correct 2 ms 1228 KB Output is correct
44 Correct 1 ms 1228 KB Output is correct
45 Correct 1 ms 1228 KB Output is correct
46 Correct 1 ms 1228 KB Output is correct
47 Correct 1 ms 1228 KB Output is correct
48 Correct 1 ms 1228 KB Output is correct
49 Correct 26 ms 2788 KB Output is correct
50 Correct 26 ms 2696 KB Output is correct
51 Correct 24 ms 2796 KB Output is correct
52 Correct 25 ms 2872 KB Output is correct
53 Correct 27 ms 2876 KB Output is correct
54 Correct 43 ms 2884 KB Output is correct
55 Correct 32 ms 2876 KB Output is correct
56 Correct 6 ms 1868 KB Output is correct
57 Correct 4 ms 1868 KB Output is correct
58 Correct 135 ms 2792 KB Output is correct
59 Correct 151 ms 2688 KB Output is correct
60 Correct 204 ms 2764 KB Output is correct
61 Correct 146 ms 2776 KB Output is correct
62 Correct 159 ms 2764 KB Output is correct
63 Correct 198 ms 2780 KB Output is correct
64 Correct 116 ms 2664 KB Output is correct
65 Correct 128 ms 2664 KB Output is correct
66 Correct 158 ms 2668 KB Output is correct
67 Correct 16 ms 1872 KB Output is correct
68 Correct 26 ms 2844 KB Output is correct
69 Correct 32 ms 2788 KB Output is correct
70 Correct 42 ms 2740 KB Output is correct
71 Correct 29 ms 2692 KB Output is correct
72 Correct 26 ms 2760 KB Output is correct
73 Correct 39 ms 2768 KB Output is correct
74 Correct 42 ms 2672 KB Output is correct