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답안 #366680

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
366680 2021-02-15T00:03:00 Z arbor Olympic Bus (JOI20_ho_t4) C++17
0 / 100
 76 ms 2796 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], c[MM], d[MM];
vi g[MN], rg[MN];
ll dis1[2][MN], dis2[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++) dis1[t][i] = 1e18, vis[i] = 0;
    dis1[t][st] = 0;
    for (int i = 0; i < N; i++) {
        int u = 0;
        for (int v = 1; v <= N; v++) {
            if (!vis[v] && dis1[t][v] < dis1[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 (dis1[t][v] > dis1[t][u] + w) {
                dis1[t][v] = dis1[t][u] + w;
                from[t][v] = e;
            }
        }
    }
}

void rdijk(int t, int st) {
    for (int i = 0; i <= N; i++) dis2[t][i] = 1e18, vis[i] = 0;
    dis2[t][st] = 0;
    for (int i = 0; i < N; i++) {
        int u = 0;
        for (int v = 1; v <= N; v++) {
            if (!vis[v] && dis2[t][v] < dis2[t][u]) {
                u = v;
            }
        }
        if (!u) break;
        vis[u] = 1;
        for (int e : rg[u]) {
            int v = b[e], w = c[e];
            if (dis2[t][v] > dis2[t][u] + w) {
                dis2[t][v] = dis2[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 = dis1[0][N] + dis1[1][1];
    int cur = N;
    while (from[0][cur]) {
        used[from[0][cur]] = 1;
        cur = a[from[0][cur]];
    }
    cur = 1;
    while (from[1][cur]) {
        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 = dis1[0][v] + w + dis2[0][u] + dis1[1][v] + w + dis2[1][u];
            mn = min(mn, dis1[1][1] + dis1[0][v] + w + dis2[0][u]);
            mn = min(mn, dis1[0][N] + dis1[1][v] + w + dis2[1][u]);
            mn += d[i];
            ans = min(ans, mn);
        }
    }
    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, dis1[0][N] + dis1[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:93:13: warning: unused variable 'u' [-Wunused-variable]
   93 |         int u = a[i], v = b[i], w = c[i];
      |             ^
ho_t4.cpp:93:33: warning: unused variable 'w' [-Wunused-variable]
   93 |         int u = a[i], v = b[i], w = c[i];
      |                                 ^

Subtask #1
0 / 5.0

# 결과 실행 시간 메모리 Grader output
1 Correct 8 ms 384 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 4 ms 492 KB Output is correct
4 Correct 6 ms 492 KB Output is correct
5 Correct 1 ms 492 KB Output is correct
6 Correct 1 ms 376 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 2 ms 492 KB Output is correct
10 Correct 57 ms 640 KB Output is correct
11 Correct 76 ms 492 KB Output is correct
12 Correct 74 ms 748 KB Output is correct
13 Incorrect 1 ms 492 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #2
0 / 11.0

# 결과 실행 시간 메모리 Grader output
1 Correct 33 ms 1900 KB Output is correct
2 Incorrect 27 ms 2796 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #3
0 / 21.0

# 결과 실행 시간 메모리 Grader output
1 Correct 5 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 20 ms 1516 KB Output is correct
4 Correct 1 ms 492 KB Output is correct
5 Correct 22 ms 2796 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Incorrect 21 ms 2796 KB Output isn't correct
9 Halted 0 ms 0 KB -

Subtask #4
0 / 63.0

# 결과 실행 시간 메모리 Grader output
1 Correct 8 ms 384 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 4 ms 492 KB Output is correct
4 Correct 6 ms 492 KB Output is correct
5 Correct 1 ms 492 KB Output is correct
6 Correct 1 ms 376 KB Output is correct
7 Correct 1 ms 364 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 2 ms 492 KB Output is correct
10 Correct 57 ms 640 KB Output is correct
11 Correct 76 ms 492 KB Output is correct
12 Correct 74 ms 748 KB Output is correct
13 Incorrect 1 ms 492 KB Output isn't correct
14 Halted 0 ms 0 KB -