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Submission #958468

# Submission time Handle Problem Language Result Execution time Memory
958468 2024-04-05T20:38:51 Z BhavayGoyal Olympic Bus (JOI20_ho_t4) C++14
5 / 100
 81 ms 7660 KB 
#include <bits/stdc++.h>
using namespace std;

#define int long long
#define vi vector<int>
#define vii vector<vector<int>>
#define pii pair<int, int>
#define pb push_back
#define f first
#define s second
#define endl "\n"

const int linf = 1e15;

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

const int N = 201, M = 50001;
int n, m;
set<pii> g[N];
vii edges;
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() {
    cin >> n >> m;
    vii dist(n+1, vi(n+1, linf));
    for (int i = 1; i <= n; i++) dist[i][i] = 0;

    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);
        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}];
        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}];
        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 = min(linf, 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}]) {
            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});
        }
        else {
            // 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);
            int A = min(dist[1][n], dist[1][b] + c + dist[a][n]);
            int B = min(dist[n][1], dist[n][b] + c + dist[a][1]);
            if (A < linf && B < linf) {
                ans = min(ans, A + B + d);
            }
        }
    }

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

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

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

Compilation message

ho_t4.cpp: In function 'void sol()':
ho_t4.cpp:62:13: warning: variable 'temp' set but not used [-Wunused-but-set-variable]
   62 |         pii temp = edge[{par[c], c}];
      |             ^~~~
ho_t4.cpp:70:13: warning: variable 'temp' set but not used [-Wunused-but-set-variable]
   70 |         pii temp = edge[{par[c], c}];
      |             ^~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 860 KB Output is correct
2 Correct 7 ms 836 KB Output is correct
3 Correct 8 ms 860 KB Output is correct
4 Correct 9 ms 860 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Correct 7 ms 604 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 16 ms 604 KB Output is correct
10 Correct 31 ms 992 KB Output is correct
11 Correct 33 ms 1008 KB Output is correct
12 Correct 32 ms 1016 KB Output is correct
13 Correct 7 ms 860 KB Output is correct
14 Correct 10 ms 860 KB Output is correct
15 Correct 9 ms 860 KB Output is correct
16 Correct 8 ms 860 KB Output is correct

Subtask #2
0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 81 ms 7012 KB Output is correct
2 Correct 62 ms 6916 KB Output is correct
3 Correct 73 ms 6952 KB Output is correct
4 Incorrect 9 ms 860 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #3
0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 860 KB Output is correct
2 Correct 7 ms 860 KB Output is correct
3 Correct 42 ms 6476 KB Output is correct
4 Correct 7 ms 604 KB Output is correct
5 Correct 49 ms 7660 KB Output is correct
6 Correct 1 ms 544 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 51 ms 7636 KB Output is correct
9 Correct 42 ms 7272 KB Output is correct
10 Correct 50 ms 6412 KB Output is correct
11 Correct 40 ms 6532 KB Output is correct
12 Correct 42 ms 6532 KB Output is correct
13 Incorrect 1 ms 344 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 860 KB Output is correct
2 Correct 7 ms 836 KB Output is correct
3 Correct 8 ms 860 KB Output is correct
4 Correct 9 ms 860 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Correct 7 ms 604 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 16 ms 604 KB Output is correct
10 Correct 31 ms 992 KB Output is correct
11 Correct 33 ms 1008 KB Output is correct
12 Correct 32 ms 1016 KB Output is correct
13 Correct 7 ms 860 KB Output is correct
14 Correct 10 ms 860 KB Output is correct
15 Correct 9 ms 860 KB Output is correct
16 Correct 8 ms 860 KB Output is correct
17 Correct 81 ms 7012 KB Output is correct
18 Correct 62 ms 6916 KB Output is correct
19 Correct 73 ms 6952 KB Output is correct
20 Incorrect 9 ms 860 KB Output isn't correct
21 Halted 0 ms 0 KB -