Submission #699382

#	Time	Username	Problem	Language	Result	Execution time	Memory
699382		CatalinT	Travelling Merchant (APIO17_merchant)	C++17	0 / 100	495 ms	2912 KiB

merchant

#include <vector>
#include <iostream>
#include <cassert>
#include <algorithm>
#include <numeric>
#include <iostream>
#include <set>
#include <map>
#include <string>
#include <unordered_map>
#include <functional>
#include <bitset>
#include <sstream>

using namespace std;

using int64 = long long;

const double EPS = 1e-9;
const int INF = (1<<30);

struct Market {
    int b;
    int s;
};

int N, M, K;
vector<vector<Market>> market;
vector<vector<int>> dist;

vector<vector<pair<int, int>>> edges;

bool go(long double r) {
    vector<long double> d(N, 1e18);

    d[0] = 0;

    for (int steps = 0; steps <= N; steps++) {
        for (int i = 0; i < N; i++) {
            for (int j = 0; j < N; j++) {
                if (dist[i][j] != INF) {
                    long double w =
                        edges[i][j].second - edges[i][j].first * r;
                    // cerr << edges[i][j].second << " -> " << edges[i][j].first  << "\n";
                    if (d[j] > d[i] + w + EPS) {
                        if (steps == N) {
                            // negative cycle
                            return true;
                        }

                        d[j] = d[i] + w;
                    }
                }
            }
        }

        // for (int i = 0; i < N; i++) {
        //     cerr << d[i] << " ";
        // }
        // cerr << "\n";
    }

    return false;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> N >> M >> K;
    market = vector<vector<Market>>(N, vector<Market>(K));

    for (int i = 0; i < N; i++) {
        for (int j = 0; j < K; j++) {
            cin >> market[i][j].b >> market[i][j].s;
        }
    }

    dist = vector<vector<int>>(N, vector<int>(N, INF));

    for (int i = 0; i < M; i++) {
        int x, y, w;
        cin >> x >> y >> w;
        x--, y--;
        dist[x][y] = min(dist[x][y], w);
    }

    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            for (int k = 0; k < N; k++) {
                if (i != k && k != j && j != i && dist[i][k] < INF && dist[k][j] < INF) {
                    dist[i][j] = min(dist[i][j], dist[i][k] + dist[k][j]);
                }
            }
        }
    }

    edges = vector<vector<pair<int, int>>>(N, vector<pair<int, int>>(N, {0, 0}));

    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            if (dist[i][j] < INF) {
                // i -> j

                int up = 0;

                for (int k = 0; k < K; k++) {
                    if (market[i][k].b != -1 && market[j][k].s != -1) {
                        up = max(up, market[j][k].s - market[i][k].b);
                    }
                }

                edges[i][j] = {up, dist[i][j]};
            }
        }
    }

    long double l = 1e-9, r = 1e18;

    while (l + EPS <= r) {
        auto m = (l + r) / 2;

        // cerr << l << " " << r << "\n";

        if (go(m)) {
            r = m;
        } else {
            l = m;
        }
    }

    auto inv = 1.0 / l;
    cout << (int64) inv << "\n";

    return 0;
}

• Subtask 1: 0 / 12
• Subtask 2: 0 / 21
• Subtask 3: 0 / 33
• Subtask 4: 0 / 34