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Submission #958440

# Submission time Handle Problem Language Result Execution time Memory
958440 2024-04-05T19:22:18 Z BhavayGoyal Olympic Bus (JOI20_ho_t4) C++14
0 / 100
 58 ms 11020 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;
        int new1n = dist[1][b] + c + dist[a][n];
        int newn1 = dist[n][b] + c + dist[a][1];
        ans = min(ans, dist[1][n] + newn1 + d);
        ans = min(ans, dist[n][1] + new1n + d);
        ans = min(ans, new1n + newn1 + d);
    }

    for (auto i : shortestEdges) {
        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
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 1116 KB Output is correct
2 Correct 8 ms 860 KB Output is correct
3 Correct 11 ms 996 KB Output is correct
4 Correct 10 ms 1072 KB Output is correct
5 Correct 1 ms 860 KB Output is correct
6 Correct 8 ms 860 KB Output is correct
7 Correct 0 ms 604 KB Output is correct
8 Correct 1 ms 604 KB Output is correct
9 Incorrect 1 ms 860 KB Output isn't correct
10 Halted 0 ms 0 KB -

Subtask #2
0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 55 ms 9520 KB Output is correct
2 Correct 54 ms 9284 KB Output is correct
3 Correct 53 ms 9680 KB Output is correct
4 Incorrect 9 ms 1116 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #3
0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 1120 KB Output is correct
2 Correct 8 ms 860 KB Output is correct
3 Correct 49 ms 9224 KB Output is correct
4 Correct 8 ms 860 KB Output is correct
5 Correct 58 ms 11020 KB Output is correct
6 Correct 0 ms 604 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 51 ms 9992 KB Output is correct
9 Correct 55 ms 9936 KB Output is correct
10 Correct 48 ms 8720 KB Output is correct
11 Correct 49 ms 8912 KB Output is correct
12 Correct 52 ms 8960 KB Output is correct
13 Incorrect 1 ms 604 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #4
0 / 63.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 1116 KB Output is correct
2 Correct 8 ms 860 KB Output is correct
3 Correct 11 ms 996 KB Output is correct
4 Correct 10 ms 1072 KB Output is correct
5 Correct 1 ms 860 KB Output is correct
6 Correct 8 ms 860 KB Output is correct
7 Correct 0 ms 604 KB Output is correct
8 Correct 1 ms 604 KB Output is correct
9 Incorrect 1 ms 860 KB Output isn't correct
10 Halted 0 ms 0 KB -