Submission #502464

#	Time	Username	Problem	Language	Result	Execution time	Memory
502464		zorianka	Commuter Pass (JOI18_commuter_pass)	C++17	31 / 100	596 ms	34568 KiB

commuter_pass

//#pragma GCC optimize("O3")

#include <bits/stdc++.h>

using namespace std;
#define MAXN 100005
#define MAXM 100005
#define mix(a, b) a = min(a,b)
using ll = long long;
const ll mod = 1e9 + 7;

vector<pair<int, ll>> g[MAXN];
vector<pair<int, ll>> gc[MAXN];

void dijkstra(vector<ll> &dist, int s) {
    dist[s] = 0;
    set<pair<ll, int>> q;
    q.insert({0, s});
    while (!q.empty()) {
        int v = q.begin()->second;
        q.erase(q.begin());
        for (auto[u, c] : g[v]) {
            if (dist[v] + c < dist[u]) {
                q.erase({dist[u], u});
                dist[u] = dist[v] + c;
                q.insert({dist[u], u});
            }
        }
    }
}

void solve() {
    int n, m;
    cin >> n >> m;
    int s, t;
    cin >> s >> t;
    int u, v;
    cin >> u >> v;
    for (int i = 0; i < m; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        g[a].emplace_back(b, c);
        g[b].emplace_back(a, c);
        gc[a].emplace_back(b, c);
        gc[b].emplace_back(a, c);
    }
    vector<ll> ds(n + 1, 1e18), dt(n + 1, 1e18);
    dijkstra(ds, s);
    dijkstra(dt, t);
    ll dist = ds[t];
    for (int w = 1; w <= n; w++) {
        for (int i = 0; i < g[w].size(); i++) {
            int to = g[w][i].first;
            ll c = g[w][i].second;
            if (ds[w] < ds[to]) {
                if (ds[w] + c + dt[to] == dist)
                    g[w][i].second = 0;
            }
        }
    }
    vector<ll> bebra(n + 1, 1e18);
    dijkstra(bebra, u);
    ll ans = bebra[v];
//    for (int w = 1; w <= n; w++) {
//        for (int i = 0; i < g[w].size(); i++) {
//            int to = g[w][i].first;
//            ll c = g[w][i].second;
//            if (dt[w] < dt[to]) {
//                if (dt[w] + c + ds[to] == dist)
//                    g[w][i].second = 0;
//            } else
//                g[w][i].second = gc[w][i].second;
//        }
//    }
    bebra.assign(n + 1, 1e18);
    dijkstra(bebra, v);
    cout << min(bebra[u],ans);
}

signed main() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
#endif
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t = 1;
//    cin >> t;
    while (t--)
        solve();
    return 0;
}

Compilation message (stderr)

commuter_pass.cpp: In function 'void solve()':
commuter_pass.cpp:52:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   52 |         for (int i = 0; i < g[w].size(); i++) {
      |                         ~~^~~~~~~~~~~~~

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45