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Submission #958460

# Submission time Handle Problem Language Result Execution time Memory
958460 2024-04-05T20:29:05 Z BhavayGoyal Olympic Bus (JOI20_ho_t4) C++14
5 / 100
 82 ms 7764 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 = 1e15;

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++) if (i != 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++) {
                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);

            // tempy thing
            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]);
            ans = min(ans, A + B + d);
        }
    }

    cout << (ans>=1e10?-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

# Verdict Execution time Memory Grader output
1 Correct 9 ms 856 KB Output is correct
2 Correct 7 ms 604 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 1112 KB Output is correct
6 Correct 8 ms 860 KB Output is correct
7 Correct 0 ms 600 KB Output is correct
8 Correct 1 ms 600 KB Output is correct
9 Correct 13 ms 856 KB Output is correct
10 Correct 25 ms 860 KB Output is correct
11 Correct 29 ms 1032 KB Output is correct
12 Correct 28 ms 1000 KB Output is correct
13 Correct 8 ms 856 KB Output is correct
14 Correct 8 ms 856 KB Output is correct
15 Correct 8 ms 856 KB Output is correct
16 Correct 8 ms 984 KB Output is correct

Subtask #2
0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 73 ms 7040 KB Output is correct
2 Correct 61 ms 6920 KB Output is correct
3 Correct 82 ms 7236 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 860 KB Output is correct
3 Correct 42 ms 6508 KB Output is correct
4 Correct 8 ms 860 KB Output is correct
5 Correct 49 ms 7764 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Correct 0 ms 604 KB Output is correct
8 Correct 39 ms 7148 KB Output is correct
9 Correct 42 ms 7184 KB Output is correct
10 Correct 44 ms 6416 KB Output is correct
11 Correct 40 ms 6416 KB Output is correct
12 Correct 48 ms 6416 KB Output is correct
13 Incorrect 1 ms 604 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 856 KB Output is correct
2 Correct 7 ms 604 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 1112 KB Output is correct
6 Correct 8 ms 860 KB Output is correct
7 Correct 0 ms 600 KB Output is correct
8 Correct 1 ms 600 KB Output is correct
9 Correct 13 ms 856 KB Output is correct
10 Correct 25 ms 860 KB Output is correct
11 Correct 29 ms 1032 KB Output is correct
12 Correct 28 ms 1000 KB Output is correct
13 Correct 8 ms 856 KB Output is correct
14 Correct 8 ms 856 KB Output is correct
15 Correct 8 ms 856 KB Output is correct
16 Correct 8 ms 984 KB Output is correct
17 Correct 73 ms 7040 KB Output is correct
18 Correct 61 ms 6920 KB Output is correct
19 Correct 82 ms 7236 KB Output is correct
20 Incorrect 9 ms 860 KB Output isn't correct
21 Halted 0 ms 0 KB -