Submission #657544

#	Time	Username	Problem	Language	Result	Execution time	Memory
657544		Alexandruabcde	Travelling Merchant (APIO17_merchant)	C++14	0 / 100	1065 ms	3600 KiB

merchant

#include <bits/stdc++.h>

using namespace std;

typedef long long LL;
typedef pair <int, int> PII;
constexpr LL INF = 1LL * 1e15;
constexpr int NMAX = 102;
constexpr int KMAX = 1002;

int N, M, K;
LL dp[NMAX][KMAX];
int lg[NMAX][KMAX];
bool use[NMAX][KMAX];

LL B[NMAX][NMAX];
LL S[NMAX][NMAX];

vector <PII> G[NMAX];

void Read () {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> N >> M >> K;

    for (int i = 1; i <= N; ++ i )
        for (int j = 1; j <= K; ++ j )
            cin >> B[i][j] >> S[i][j];

    for (int i = 1; i <= M; ++ i ) {
        int x, y, t;
        cin >> x >> y >> t;

        G[x].push_back({y, t});
    }
}

/*
(sell - buy) / time >= r
sell - buy - time * r >= 0
buy + time * r - sell <= 0 ?
*/

bool BFS (int Start, LL r) {
    for (int i = 1; i <= N; ++ i )
        for (int j = 0; j <= K; ++ j ) {
            dp[i][j] = INF;
            lg[i][j] = 0;
            use[i][j] = false;
        }

    dp[Start][0] = 0;
    use[Start][0] = true;
    lg[Start][0] = 1;

    queue <PII> Q;
    Q.push({Start, 0});

    while (!Q.empty()) {
        int i = Q.front().first;
        int j = Q.front().second;
        Q.pop();
        use[i][j] = false;

        ///dau sell
        if (j != 0) {
            if (dp[i][0] > dp[i][j] - S[i][j]) {
                dp[i][0] = dp[i][j] + S[i][j];
                lg[i][0] = lg[i][j];

                if (!use[i][0]) {
                    Q.push({i, 0});
                    use[i][0] = true;
                }
            }
        }

        ///buy
        if (j == 0) {
            for (int k = 1; k <= K; ++ k ) {
                if (dp[i][k] > dp[i][0] + B[i][k]) {
                    dp[i][k] = dp[i][0] + B[i][k];
                    lg[i][k] = lg[i][j];

                    if (!use[i][k]) {
                        Q.push({i, k});
                        use[i][k] = true;
                    }
                }
            }
        }

        for (auto it : G[i]) {
            int to = it.first;
            LL cost_scad = r * it.second;

            if (dp[to][j] > dp[i][j] + cost_scad) {
                dp[to][j] = dp[i][j] + cost_scad;
                lg[to][j] = lg[i][j] + 1;

                if (lg[to][j] > N)
                    return true;

                if (!use[to][j]) {
                    use[to][j] = true;
                    Q.push({to, j});
                }
            }
        }
    }

    return false;
}

void Solve () {
    LL st = 1, dr = 100, ans = 0;

    while (st <= dr) {
        LL mij = (st + dr) / 2;

        if (BFS(1, mij)) {
            st = mij + 1;
            ans = mij;
        }
        else dr = mij - 1;
    }

    cout << ans << '\n';
}

int main () {
    Read();
    Solve();

    return 0;
}

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