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Submission #958436

# Submission time Handle Problem Language Result Execution time Memory
958436 2024-04-05T19:16:24 Z BhavayGoyal Olympic Bus (JOI20_ho_t4) C++14
5 / 100
 1000 ms 8464 KB 
#include <bits/stdc++.h>
using namespace std;

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;

template<class T> using oset = 
            tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

#define int long long
#define ld long double
#define ar array
#define vi vector<int>
#define vii vector<vector<int>>
#define pii pair<int, int>
#define pb push_back
#define all(x) x.begin(), x.end()
#define f first
#define s second
#define endl "\n"

const int MOD = 1e9+7;
const int inf = 1e9;
const int linf = 1e15;

const int d4i[4]={-1, 0, 1, 0}, d4j[4]={0, 1, 0, -1};
const int d8i[8]={-1, -1, 0, 1, 1, 1, 0, -1}, d8j[8]={0, 1, 1, 1, 0, -1, -1, -1};

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());


// -------------------------------------------------- Main Code --------------------------------------------------

const int N = 205, M = 50005;
int n, m, dist[N][N];
set<pii> g[N];
vii edges, shortestEdges;
map<pair<int, int>, bool> isShort;
map<pii, pii> edge;

pair<vi, vi> dijkstra(int source) {
    priority_queue<pii, vector<pii>, greater<>> q;
    vi vis(n+1, 0), dis(n+1, linf), par(n+1);
    q.push({0, source});
    dis[source] = 0;
    while (!q.empty()) {
        pii f = q.top(); q.pop();
        int src = f.s;
        if (vis[src]) continue;
        vis[src] = true;

        for (auto child : g[src]) {
            int ch = child.f, wt = child.s;
            if (dis[ch] > dis[src] + wt) {
                par[ch] = src;
                dis[ch] = dis[src] + wt;
                q.push({dis[ch], ch});
            }
        }
    }
    return {dis, par};
}

void sol() {
    for (int i = 0; i < N; i++) for (int j = 0; j < N; j++) if (i != j) dist[i][j] = linf;

    cin >> n >> m;
    for (int i = 1; i <= m; i++) {
        int a, b, c, d; cin >> a >> b >> c >> d;
        dist[a][b] = min(dist[a][b], c);
        edge[{a, b}] = {c, d};
        g[a].insert({b, c});
        edges.pb({a, b, c, d});
    }

    pair<vi, vi> x = dijkstra(1); vi dis = x.f, par = x.s;
    int c = n;
    while (par[c]) {
        pii temp = edge[{par[c], c}];
        shortestEdges.pb({par[c], c, temp.f, temp.s});
        isShort[{par[c], c}] = true;
        c = par[c];
    }

    x = dijkstra(n); dis = x.f, par = x.s;
    c = 1;
    while (par[c]) {
        pii temp = edge[{par[c], c}];
        shortestEdges.pb({par[c], c, temp.f, temp.s});
        isShort[{par[c], c}] = true;
        c = par[c];
    }

    for (int k = 1; k <= n; k++) {
        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= n; j++) {
                dist[i][j] = min(dist[i][j], dist[i][k] + dist[k][j]);
            }
        }
    }

    int ans = dist[1][n] + dist[n][1];

    for (auto i : edges) {
        int a = i[0], b = i[1], c = i[2], d = i[3];
        if (isShort[{a, b}]) continue;
        ans = min(ans, dist[1][n] + dist[n][b] + c + dist[a][1] + d);
        ans = min(ans, dist[n][1] + dist[1][b] + c + dist[a][n] + d);
    }

    for (auto i : edges) {
        int a = i[0], b = i[1], c = i[2], d = i[3];
        g[a].erase({b, c});
        g[b].insert({a, c});
        pair<vi, vi> x = dijkstra(1);
        pair<vi, vi> y = dijkstra(n);
        ans = min(ans, x.f[n] + y.f[1] + d);
        g[b].erase({a, c});
        g[a].insert({b, c});
    }

    cout << (ans>=1e10?-1:ans) << endl;
}

signed main () {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int t = 1;
    // cin >> t; 
    while (t--) {
        sol();
    }
    return 0;
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 33 ms 860 KB Output is correct
2 Correct 9 ms 872 KB Output is correct
3 Correct 53 ms 1080 KB Output is correct
4 Correct 57 ms 860 KB Output is correct
5 Correct 19 ms 1028 KB Output is correct
6 Correct 9 ms 860 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 604 KB Output is correct
9 Correct 13 ms 936 KB Output is correct
10 Correct 78 ms 1116 KB Output is correct
11 Correct 84 ms 1112 KB Output is correct
12 Correct 81 ms 1116 KB Output is correct
13 Correct 30 ms 860 KB Output is correct
14 Correct 36 ms 1084 KB Output is correct
15 Correct 31 ms 856 KB Output is correct
16 Correct 36 ms 860 KB Output is correct

Subtask #2
0 / 11.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1071 ms 8464 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #3
0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 856 KB Output is correct
2 Correct 9 ms 860 KB Output is correct
3 Execution timed out 1072 ms 8464 KB Time limit exceeded
4 Halted 0 ms 0 KB -

Subtask #4
0 / 63.0

# Verdict Execution time Memory Grader output
1 Correct 33 ms 860 KB Output is correct
2 Correct 9 ms 872 KB Output is correct
3 Correct 53 ms 1080 KB Output is correct
4 Correct 57 ms 860 KB Output is correct
5 Correct 19 ms 1028 KB Output is correct
6 Correct 9 ms 860 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 604 KB Output is correct
9 Correct 13 ms 936 KB Output is correct
10 Correct 78 ms 1116 KB Output is correct
11 Correct 84 ms 1112 KB Output is correct
12 Correct 81 ms 1116 KB Output is correct
13 Correct 30 ms 860 KB Output is correct
14 Correct 36 ms 1084 KB Output is correct
15 Correct 31 ms 856 KB Output is correct
16 Correct 36 ms 860 KB Output is correct
17 Execution timed out 1071 ms 8464 KB Time limit exceeded
18 Halted 0 ms 0 KB -