Submission #723438

#	Time	Username	Problem	Language	Result	Execution time	Memory
723438		piOOE	Escape Route (JOI21_escape_route)	C++17	0 / 100	9068 ms	313564 KiB

escape_route

#include "escape_route.h"
#include <bits/stdc++.h>

using namespace std;
using ll = long long;

vector<ll> calculate_necessary_time(int n, int m, ll S, int q, vector<int> A, vector<int> B, vector<ll> L, vector<ll> C,
                                    vector<int> U, vector<int> V, vector<ll> T) {

    vector<ll> answer(q);

    vector<vector<int>> queries(n);

    for (int i = 0; i < q; ++i) {
        queries[U[i]].push_back(i);
    }

    vector<vector<pair<int, int>>> adj(n);

    for (int i = 0; i < m; ++i) {
        adj[A[i]].emplace_back(B[i], i);
        adj[B[i]].emplace_back(A[i], i);
    }

    constexpr ll inf = 3e18;

    auto dijkstra = [&](int source, ll s, bool rev = false) -> vector<ll> {
        vector<ll> dist(n, rev ? -inf : inf);
        dist[source] = s;

        vector<bool> used(n);

        for (int _ = 0; _ < n; ++_) {
            int v = -1;

            for (int i = 0; i < n; ++i) {
                if (!used[i] && (v == -1 || rev ^ (dist[i] < dist[v]))) {
                    v = i;
                }
            }

            used[v] = true;

            for (auto [to, i] : adj[v]) {
                ll d;

                if (rev) {
                    d = min(dist[v], C[i]) - L[i];
                } else {
                    d = L[i] + (dist[v] % S <= C[i] - L[i] ? dist[v] : (dist[v] / S + 1) * S);
                }

                if (rev ^ (dist[to] > d)) {
                    dist[to] = d;
                }
            }
        }

        for (int i = 0; i < n; ++i) {
            dist[i] = rev ? s - dist[i] : dist[i] - s;
        }

        return dist;
    };

    vector from(n, vector<ll>(n));

    for (int i = 0; i < n; ++i) {
        from[i] = dijkstra(i, 0);
    }

    vector dto(n, vector<ll>(n));

    for (int i = 0; i < n; ++i) {
        dto[i] = dijkstra(i, S - 1, true);
    }

    vector most(n, vector<ll>(n));

    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < n; ++j) {
            if (i == j) {
                most[i][j] = inf;
                continue;
            }

            ll lo = -1, hi = S;

            while (lo + 1 < hi) {
                ll mid = (lo + hi) / 2;

                if (mid + dijkstra(i, mid)[j] < S) {
                    lo = mid;
                } else {
                    hi = mid;
                }
            }

            most[i][j] = lo;
        }
    }

    for (int i = 0; i < n; ++i) {
        vector<ll> till;
        vector<vector<ll>> dp;

        int dead = 0;

        for (int j = 0; dead < m; ++j) {
            till.push_back(0);
            dp.emplace_back();

            ll s = j > 0 ? till[j - 1] + 1 : 0;
            dead = 0;

            if (s < S) {
                vector<ll> d = dijkstra(i, s);

                for (int to = 0; to < n; ++to) {
                    if (d[to] + s >= S) {
                        d[to] = inf;
                    }
                }

                dp[j] = d;
                ll nxt = inf;

                for (int k = 0; k < m; ++k) {
                    if (d[A[k]] > d[B[k]]) {
                        swap(A[k], B[k]);
                    }

                    if (C[k] - L[k] >= d[A[k]]) {
                        nxt = min(nxt, C[k] - L[k] - d[A[k]]);
                    } else {
                        dead += 1;
                    }
                }

                till[j] = s + nxt;
            } else {
                dp[j] = vector(n, inf);
                till[j] = inf;
                dead = m;
            }
        }

        for (int j : queries[i]) {
            ll ans = inf;
            int to = V[j];

            for (int mid = 0; mid < n; ++mid) {
                ll dist = most[i][mid] < T[j] ? inf : S - 1 - T[j] + 1 + from[mid][to];
                ans = min(ans, dist);
            }

            int k = lower_bound(till.begin(), till.end(), T[j]) - till.begin();

            if (k < dp.size()) {
                ans = min(ans, dp[k][to]);
            }

            answer[j] = ans;
        }
    }

    return answer;
}

Compilation message (stderr)

escape_route.cpp: In function 'std::vector<long long int> calculate_necessary_time(int, int, ll, int, std::vector<int>, std::vector<int>, std::vector<long long int>, std::vector<long long int>, std::vector<int>, std::vector<int>, std::vector<long long int>)':
escape_route.cpp:159:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<long long int>, std::allocator<std::vector<long long int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  159 |             if (k < dp.size()) {
      |                 ~~^~~~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 20
• Subtask 3: 0 / 10
• Subtask 4: 0 / 35
• Subtask 5: 0 / 30