Submission #415147

#	Time	Username	Problem	Language	Result	Execution time	Memory
415147		meatrow	Commuter Pass (JOI18_commuter_pass)	C++17	31 / 100	862 ms	27452 KiB

commuter_pass

// #pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ld = long double;

const int MOD = 1e9 + 7;

ll binpow(ll a, ll p, int mod = MOD) {
    ll res = 1;
    while (p) {
        if (p & 1) {
            (res *= a) %= mod;
        }
        p >>= 1;
        (a *= a) %= mod;
    }
    return res;
}

ll gcd(ll a, ll b) {
    return b == 0 ? a : gcd(b, a % b);
}

void solve() {
    int n, m;
    int S, T;
    int U, V;
    cin >> n >> m >> S >> T >> U >> V;
    vector<vector<pair<int, ll>>> g(n + 1);
    for (int i = 0; i < m; i++) {
        int a, b;
        ll c;
        cin >> a >> b >> c;
        g[a].emplace_back(b, c);
        g[b].emplace_back(a, c);
    }

    auto getDist = [&](int from) {
        vector<ll> dist(n + 1, 1e18);
        dist[from] = 0;
        set<pair<ll, int>> setik;
        setik.insert({0, from});
        while (!setik.empty()) {
            int v = setik.begin()->second;
            setik.erase(setik.begin());
            for (auto& [u, w] : g[v]) {
                if (dist[v] + w < dist[u]) {
                    setik.erase({dist[u], u});
                    dist[u] = dist[v] + w;
                    setik.insert({dist[u], u});
                }
            }
        }
        return dist;
    };

    vector<ll> distS = getDist(S);
    vector<ll> distT = getDist(T);
    vector<ll> distU = getDist(U);
    vector<ll> distV = getDist(V);

    ll ans = distU[V];
    vector<int> used(n + 1);
    vector<ll> dp(n + 1), pd(n + 1);
    function<void(int)> dfs = [&](int v) {
        used[v] = 1;
        dp[v] = distV[v];
        pd[v] = distU[v];
        for (auto& [u, w] : g[v]) {
            if (used[u] || distS[v] + w + distT[u] > distS[T]) continue;
            dfs(u);
            dp[v] = min(dp[v], dp[u]);
            pd[v] = min(pd[v], pd[u]);
        }
        ans = min(ans, distU[v] + dp[v]);
        ans = min(ans, distV[v] + pd[v]);
    };
    dfs(S);

    cout << ans << endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int T = 1;
    // cin >> T;
    for (int tc = 1; tc <= T; tc++) {
        // cout << "Case #" << tc << ": ";
        solve();
    }
    return 0;
}

Compilation message (stderr)

commuter_pass.cpp:2: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    2 | #pragma GCC optimization ("O3")
      |

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