Submission #101039

#	Time	Username	Problem	Language	Result	Execution time	Memory
101039		oolimry	Travelling Merchant (APIO17_merchant)	C++14	100 / 100	150 ms	2340 KiB

merchant

#include <bits/stdc++.h>
using namespace std;
long long inf = 1000000000000000ll;
int main()
{
    int n, m, t;
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> m >> t;

    static long long buy[105][1005];
    static long long sell[105][1005];
    static long long dist[105][105];
    static long long profit[105][105];

    for(int i = 0;i < n;i++){
        for(int j = 0;j < n;j++){
            buy[i][j] = inf;
            sell[i][j] = inf;
            profit[i][j] = 0;
            dist[i][j] = inf;
        }
    }

    for(int i = 0;i < n;i++){
        for(int k = 0;k < t;k++){
            cin >> buy[i][k];
            cin >> sell[i][k];
        }
    }

    ///Max Profit btw two nodes
    for(int i = 0;i < n;i++){
        for(int j = 0;j < n;j++){
            for(int k = 0;k < t;k++){
                if(buy[i][k] != -1 && sell[j][k] != -1)
                    profit[i][j] = max(profit[i][j],sell[j][k] -  buy[i][k]);

            }
        }
    }

    ///adjMat
    for(int i = 0;i < m;i++){
        int a, b, c;
        cin >> a >> b >> c;
        a--;
        b--;
        dist[a][b] = c;
    }

    ///Floyd
    for(int k = 0;k < n;k++){
        for(int i = 0;i < n;i++){
            for(int j = 0;j < n;j++){
                dist[i][j] = min(dist[i][j], dist[i][k] + dist[k][j]);
            }
        }
    }

    ///p/d >= v
    ///p - dv >= 0 for a cycle, where p is total profit, d is total distance
    ///monotonous in terms of v
    static long long diff[105][105];

    long long low = 0ll;
    long long high = inf;
    while(true){
        if(low == high - 1) break;
        long long v = (low + high) / 2ll;
        for(int i =0 ;i < n;i++){
            for(int j = 0;j < n;j++){
                ///new graph with edge weight = p - dv
                diff[i][j] = profit[i][j] - v * min(inf/v,dist[i][j]);
            }
        }

        ///Floyd
        for(int k = 0;k < n;k++){
            for(int i = 0;i < n;i++){
                for(int j = 0;j < n;j++){
                    diff[i][j] = max(diff[i][j], diff[i][k] + diff[k][j]);

                }
            }
        }

        bool can = false;
        for(int i = 0;i < n;i++){
            if(diff[i][i] >= 0){
                can = true;
                break;
            }
        }
        if(can) low = v;
        else high = v;
    }
    cout << low;
    return 0;
}

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