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답안 #958463

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
958463 2024-04-05T20:31:08 Z BhavayGoyal Olympic Bus (JOI20_ho_t4) C++14
5 / 100
 79 ms 7680 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 = 1e18;

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;
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++) 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);
        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++) {
                if (i == j) dist[i][j] = 0;
                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}]) {
            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);
        }
    }

    cout << (ans>=1e15?-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:79:13: warning: variable 'temp' set but not used [-Wunused-but-set-variable]
   79 |         pii temp = edge[{par[c], c}];
      |             ^~~~
ho_t4.cpp:87:13: warning: variable 'temp' set but not used [-Wunused-but-set-variable]
   87 |         pii temp = edge[{par[c], c}];
      |             ^~~~

Subtask #1
5.0 / 5.0

# 결과 실행 시간 메모리 Grader output
1 Correct 10 ms 860 KB Output is correct
2 Correct 9 ms 604 KB Output is correct
3 Correct 10 ms 860 KB Output is correct
4 Correct 10 ms 860 KB Output is correct
5 Correct 1 ms 860 KB Output is correct
6 Correct 9 ms 860 KB Output is correct
7 Correct 0 ms 604 KB Output is correct
8 Correct 0 ms 604 KB Output is correct
9 Correct 13 ms 860 KB Output is correct
10 Correct 26 ms 860 KB Output is correct
11 Correct 31 ms 1044 KB Output is correct
12 Correct 30 ms 1008 KB Output is correct
13 Correct 9 ms 860 KB Output is correct
14 Correct 11 ms 968 KB Output is correct
15 Correct 10 ms 956 KB Output is correct
16 Correct 10 ms 856 KB Output is correct

Subtask #2
0 / 11.0

# 결과 실행 시간 메모리 Grader output
1 Correct 79 ms 6804 KB Output is correct
2 Correct 64 ms 6920 KB Output is correct
3 Correct 73 ms 6912 KB Output is correct
4 Incorrect 11 ms 856 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #3
0 / 21.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 956 KB Output is correct
2 Correct 9 ms 860 KB Output is correct
3 Correct 44 ms 6528 KB Output is correct
4 Correct 9 ms 600 KB Output is correct
5 Correct 50 ms 7680 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Correct 0 ms 604 KB Output is correct
8 Correct 42 ms 7160 KB Output is correct
9 Correct 42 ms 7148 KB Output is correct
10 Correct 44 ms 6440 KB Output is correct
11 Correct 50 ms 6920 KB Output is correct
12 Correct 44 ms 6404 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

# 결과 실행 시간 메모리 Grader output
1 Correct 10 ms 860 KB Output is correct
2 Correct 9 ms 604 KB Output is correct
3 Correct 10 ms 860 KB Output is correct
4 Correct 10 ms 860 KB Output is correct
5 Correct 1 ms 860 KB Output is correct
6 Correct 9 ms 860 KB Output is correct
7 Correct 0 ms 604 KB Output is correct
8 Correct 0 ms 604 KB Output is correct
9 Correct 13 ms 860 KB Output is correct
10 Correct 26 ms 860 KB Output is correct
11 Correct 31 ms 1044 KB Output is correct
12 Correct 30 ms 1008 KB Output is correct
13 Correct 9 ms 860 KB Output is correct
14 Correct 11 ms 968 KB Output is correct
15 Correct 10 ms 956 KB Output is correct
16 Correct 10 ms 856 KB Output is correct
17 Correct 79 ms 6804 KB Output is correct
18 Correct 64 ms 6920 KB Output is correct
19 Correct 73 ms 6912 KB Output is correct
20 Incorrect 11 ms 856 KB Output isn't correct
21 Halted 0 ms 0 KB -