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Submission #958470

# Submission time Handle Problem Language Result Execution time Memory
958470 2024-04-05T20:42:26 Z BhavayGoyal Olympic Bus (JOI20_ho_t4) C++14
5 / 100
 77 ms 7776 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 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);
            }
        }
    }

    assert(ans == linf || ans <= 1e10);
    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 10 ms 1016 KB Output is correct
2 Correct 7 ms 600 KB Output is correct
3 Correct 9 ms 952 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 12 ms 600 KB Output is correct
10 Correct 25 ms 860 KB Output is correct
11 Correct 29 ms 1112 KB Output is correct
12 Correct 34 ms 860 KB Output is correct
13 Correct 8 ms 860 KB Output is correct
14 Correct 9 ms 940 KB Output is correct
15 Correct 8 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 77 ms 6788 KB Output is correct
2 Correct 62 ms 6920 KB Output is correct
3 Correct 68 ms 6900 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 8 ms 860 KB Output is correct
2 Correct 7 ms 604 KB Output is correct
3 Correct 41 ms 6620 KB Output is correct
4 Correct 7 ms 604 KB Output is correct
5 Correct 49 ms 7776 KB Output is correct
6 Correct 0 ms 344 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 39 ms 7176 KB Output is correct
9 Correct 39 ms 7184 KB Output is correct
10 Correct 42 ms 6592 KB Output is correct
11 Correct 41 ms 6396 KB Output is correct
12 Correct 44 ms 6412 KB Output is correct
13 Incorrect 1 ms 600 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #4
0 / 63.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 1016 KB Output is correct
2 Correct 7 ms 600 KB Output is correct
3 Correct 9 ms 952 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 12 ms 600 KB Output is correct
10 Correct 25 ms 860 KB Output is correct
11 Correct 29 ms 1112 KB Output is correct
12 Correct 34 ms 860 KB Output is correct
13 Correct 8 ms 860 KB Output is correct
14 Correct 9 ms 940 KB Output is correct
15 Correct 8 ms 860 KB Output is correct
16 Correct 8 ms 860 KB Output is correct
17 Correct 77 ms 6788 KB Output is correct
18 Correct 62 ms 6920 KB Output is correct
19 Correct 68 ms 6900 KB Output is correct
20 Incorrect 9 ms 860 KB Output isn't correct
21 Halted 0 ms 0 KB -