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Submission #366681

# Submission time Handle Problem Language Result Execution time Memory
366681 2021-02-15T00:08:55 Z arbor Olympic Bus (JOI20_ho_t4) C++17
0 / 100
 71 ms 2288 KB 
#include <bits/stdc++.h>
#define all(x) begin(x), end(x)
#define sz(x) int((x).size())
#define eb emplace_back
#define pb push_back
using namespace std;
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;
const int MN = 205, MM = 5e4 + 5;
int N, M, a[MM], b[MM]; ll c[MM], d[MM];
vi g[MN], rg[MN];
ll dis[2][MN], rdis[2][MN];
int from[2][MN];
bool vis[MN];
bool used[MM];

void dijk(int t, int st) {
    for (int i = 0; i <= N; i++) dis[t][i] = 1e18, vis[i] = 0;
    dis[t][st] = 0;
    for (int i = 0; i < N; i++) {
        int u = 0;
        for (int v = 1; v <= N; v++) {
            if (!vis[v] && dis[t][v] < dis[t][u]) {
                u = v;
            }
        }
        if (!u) break;
        vis[u] = 1;
        for (int e : g[u]) {
            if (u != a[e]) continue;
            int v = b[e], w = c[e];
            if (dis[t][v] > dis[t][u] + w) {
                dis[t][v] = dis[t][u] + w;
                from[t][v] = e;
            }
        }
    }
}

void rdijk(int t, int st) {
    for (int i = 0; i <= N; i++) rdis[t][i] = 1e18, vis[i] = 0;
    rdis[t][st] = 0;
    for (int i = 0; i < N; i++) {
        int u = 0;
        for (int v = 1; v <= N; v++) {
            if (!vis[v] && rdis[t][v] < rdis[t][u]) {
                u = v;
            }
        }
        if (!u) break;
        vis[u] = 1;
        for (int e : rg[u]) {
            int v = b[e], w = c[e];
            if (rdis[t][v] > rdis[t][u] + w) {
                rdis[t][v] = rdis[t][u] + w;
            }
        }
    }
}

int main() {
    ios_base::sync_with_stdio(0), cin.tie(0);
    cin >> N >> M;
    for (int i = 1; i <= M; i++) {
        cin >> a[i] >> b[i] >> c[i] >> d[i];
        g[a[i]].pb(i), rg[b[i]].pb(i);
    }
    dijk(0, 1), dijk(1, N);
    rdijk(0, N), rdijk(1, 1);
    ll ans = dis[0][N] + dis[1][1];
    int cur = N;
    while (from[0][cur] && cur != 1) {
        used[from[0][cur]] = 1;
        cur = a[from[0][cur]];
    }
    cur = 1;
    while (from[1][cur] && cur != N) {
        used[from[1][cur]] = 1;
        cur = a[from[1][cur]];
    }
    for (int i = 1; i <= M; i++) {
        int u = a[i], v = b[i], w = c[i];
        if (!used[i]) {
            ll mn = dis[0][v] + w + rdis[0][u] + dis[1][v] + w + rdis[1][u];
            mn = min(mn, dis[1][1] + dis[0][v] + w + rdis[0][u]);
            mn = min(mn, dis[0][N] + dis[1][v] + w + rdis[1][u]);
            ans = min(ans, mn + d[i]);
        }
    }
    for (int i = 1; i <= M; i++) {
        int u = a[i], v = b[i], w = c[i];
        if (used[i]) {
            swap(a[i], b[i]);
            g[v].pb(i);
            dijk(0, 1), dijk(1, N);
            g[v].pop_back();
            swap(a[i], b[i]);
            ans = min(ans, dis[0][N] + dis[1][1] + d[i]);
        }
    }
    if (ans >= 1e18) ans = -1;
    cout << ans << '\n';
    return 0;
}

Compilation message

ho_t4.cpp: In function 'int main()':
ho_t4.cpp:92:13: warning: unused variable 'u' [-Wunused-variable]
   92 |         int u = a[i], v = b[i], w = c[i];
      |             ^
ho_t4.cpp:92:33: warning: unused variable 'w' [-Wunused-variable]
   92 |         int u = a[i], v = b[i], w = c[i];
      |                                 ^

Subtask #1
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 4 ms 364 KB Output is correct
4 Correct 5 ms 364 KB Output is correct
5 Correct 1 ms 384 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 0 ms 364 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 53 ms 364 KB Output is correct
11 Correct 71 ms 492 KB Output is correct
12 Correct 66 ms 364 KB Output is correct
13 Incorrect 1 ms 364 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #2
0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 25 ms 2248 KB Output is correct
2 Incorrect 26 ms 2288 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #3
0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 18 ms 1772 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 22 ms 2156 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Incorrect 20 ms 2212 KB Output isn't correct
9 Halted 0 ms 0 KB -

Subtask #4
0 / 63.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 4 ms 364 KB Output is correct
4 Correct 5 ms 364 KB Output is correct
5 Correct 1 ms 384 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 0 ms 364 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 53 ms 364 KB Output is correct
11 Correct 71 ms 492 KB Output is correct
12 Correct 66 ms 364 KB Output is correct
13 Incorrect 1 ms 364 KB Output isn't correct
14 Halted 0 ms 0 KB -