Submission #501139

#	Time	Username	Problem	Language	Result	Execution time	Memory
501139		Stickfish	Travelling Merchant (APIO17_merchant)	C++17	100 / 100	228 ms	5884 KiB

merchant

#include <iostream>
#include <cassert>
#include <vector>
using namespace std;
using ll = __int128;

const ll INF = 1.77013e15;
const int MAXN = 100;
const int MAXK = 1000;
ll buy[MAXN][MAXK];
ll sell[MAXN][MAXK];
ll d[MAXN][MAXN];
ll prof[MAXN][MAXN];

ll smoke[MAXN][MAXN];

signed main() {
    int n, m, k;
    cin >> n >> m >> k;
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < k; ++j) {
            long long b, s;
            cin >> b >> s;
            buy[i][j] = b;
            sell[i][j] = s;
            //cin >> buy[i][j] >> sell[i][j];
            if (buy[i][j] == -1)
                buy[i][j] = INF;
            if (sell[i][j] == -1)
                sell[i][j] = 0;
        }
    }
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < n; ++j) {
            d[i][j] = INF;
        }
        d[i][i] = 0;
    }
    for (int i = 0; i < m; ++i) {
        int u, v, w;
        cin >> u >> v >> w;
        --u, --v;
        d[u][v] = w;
    }
    for (int i = 0; i < n; ++i) {
        for (int v = 0; v < n; ++v) {
            for (int u = 0; u < n; ++u) {
                d[v][u] = min(d[v][u], d[v][i] + d[i][u]);
            }
        }
    }
    //for (int i = 0; i < n; ++i) {
        //for (int j = 0; j < n; ++j)
            //cout << d[i][j] << ' ';
        //cout << endl;
    //}
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < n; ++j) {
            for (int w = 0; w < n; ++w) {
                assert(d[i][j] + d[j][w] >= d[i][w]);
            }
        }
    }
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < n; ++j) {
            for (int t = 0; t < k; ++t) {
                prof[i][j] = max(prof[i][j], sell[j][t] - buy[i][t]);
            }
        }
        assert(prof[i][i] == 0);
    }
    //cout << endl;
    //for (int i = 0; i < n; ++i) {
        //for (int j = 0; j < n; ++j)
            //cout << prof[i][j] << ' ';
        //cout << endl;
    //}
    ll lb = 0, ub = INF;
    while (ub - lb > 1) {
        ll mb = (lb + ub) / 2;
        // (sum prof) / (sum time) >= mb
        // sum prof >= mb * (sum time)
        // sum {prof - mb * time} >= 0
        for (int i = 0; i < n; ++i) {
            for (int j = 0; j < n; ++j) {
                if (d[i][j] == INF || j == i)
                    smoke[i][j] = -INF;
                else
                    smoke[i][j] = prof[i][j] - mb * d[i][j];
            }
        }
        for (int i = 0; i < n; ++i) {
            for (int v = 0; v < n; ++v) {
                if (smoke[v][i] == -INF)
                    continue;
                for (int u = 0; u < n; ++u) {
                    if (smoke[i][u] == -INF)
                        continue;
                    smoke[v][u] = max(smoke[v][u], smoke[v][i] + smoke[i][u]);
                }
            }
        }
        //if (mb == 2) {
            //cout << endl;
            //for (int i = 0; i < n; ++i) {
                //for (int j = 0; j < n; ++j) {
                    //if (smoke[i][j] == -INF)
                        //cout << "-i ";
                    //else
                        //cout << smoke[i][j] << ' ';
                //}
                //cout << endl;
            //}
        //}
        bool isok = false;
        for (int i = 0; i < n; ++i) {
            if (smoke[i][i] >= 0) {
                isok = true;
                break;
            }
        }
        if (isok)
            lb = mb;
        else
            ub = mb;
    }
    cout << (long long)(lb) << endl;
}

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