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Submission #958462

# Submission time Handle Problem Language Result Execution time Memory
958462 2024-04-05T20:30:51 Z BhavayGoyal Olympic Bus (JOI20_ho_t4) C++14
5 / 100
 75 ms 7688 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++) 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>=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 10 ms 860 KB Output is correct
2 Correct 9 ms 852 KB Output is correct
3 Correct 10 ms 1112 KB Output is correct
4 Correct 10 ms 848 KB Output is correct
5 Correct 1 ms 856 KB Output is correct
6 Correct 9 ms 860 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 856 KB Output is correct
9 Correct 13 ms 860 KB Output is correct
10 Correct 26 ms 860 KB Output is correct
11 Correct 33 ms 860 KB Output is correct
12 Correct 32 ms 1116 KB Output is correct
13 Correct 9 ms 860 KB Output is correct
14 Correct 10 ms 952 KB Output is correct
15 Correct 10 ms 860 KB Output is correct
16 Correct 10 ms 860 KB Output is correct

Subtask #2
0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 75 ms 6916 KB Output is correct
2 Correct 63 ms 6852 KB Output is correct
3 Correct 68 ms 6912 KB Output is correct
4 Incorrect 13 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 10 ms 856 KB Output is correct
2 Correct 9 ms 848 KB Output is correct
3 Correct 47 ms 6408 KB Output is correct
4 Correct 9 ms 856 KB Output is correct
5 Correct 50 ms 7688 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 7152 KB Output is correct
9 Correct 41 ms 7324 KB Output is correct
10 Correct 45 ms 6404 KB Output is correct
11 Correct 42 ms 6396 KB Output is correct
12 Correct 43 ms 6492 KB Output is correct
13 Incorrect 0 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 860 KB Output is correct
2 Correct 9 ms 852 KB Output is correct
3 Correct 10 ms 1112 KB Output is correct
4 Correct 10 ms 848 KB Output is correct
5 Correct 1 ms 856 KB Output is correct
6 Correct 9 ms 860 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 856 KB Output is correct
9 Correct 13 ms 860 KB Output is correct
10 Correct 26 ms 860 KB Output is correct
11 Correct 33 ms 860 KB Output is correct
12 Correct 32 ms 1116 KB Output is correct
13 Correct 9 ms 860 KB Output is correct
14 Correct 10 ms 952 KB Output is correct
15 Correct 10 ms 860 KB Output is correct
16 Correct 10 ms 860 KB Output is correct
17 Correct 75 ms 6916 KB Output is correct
18 Correct 63 ms 6852 KB Output is correct
19 Correct 68 ms 6912 KB Output is correct
20 Incorrect 13 ms 860 KB Output isn't correct
21 Halted 0 ms 0 KB -