Submission #767484

#	Time	Username	Problem	Language	Result	Execution time	Memory
767484		dxz05	Travelling Merchant (APIO17_merchant)	C++17	0 / 100	47 ms	1236 KiB

merchant

#include <bits/stdc++.h>

using namespace std;

#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define bpc(x) __builtin_popcount(x)
#define bpcll(x) __builtin_popcountll(x)
#define MP make_pair
#define BIT(x, i) (((x) >> (i)) & 1)
//#define endl '\n'

mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());

typedef long long ll;
const int MOD = 1e9 + 7;
const int N = 1e6 + 3e2;

void solve(){
    int n, m, items;
    cin >> n >> m >> items;

    vector<vector<int>> B(n, vector<int>(items, -1));
    vector<vector<int>> S(n, vector<int>(items, -1));

    const long long INF = 1e18;

    vector<vector<ll>> dist(n, vector<ll>(n, INF));

    for (int i = 0; i < n; i++){
        for (int j = 0; j < items; j++) cin >> B[i][j] >> S[i][j];
        dist[i][i] = 0;
    }

    while (m--){
        int u, v, w;
        cin >> u >> v >> w;
        --u, --v;
        dist[u][v] = w;
    }

    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]);
            }
        }
    }

    vector<vector<int>> max_diff(n, vector<int>(n, 0));
    for (int i = 0; i < n; i++){
        for (int j = 0; j < n; j++){
            for (int k = 0; k < items; k++){
                if (B[i][k] == -1 || S[j][k] == -1) continue;
                max_diff[i][j] = max(max_diff[i][j], S[j][k] - B[i][k]);
            }
        }
    }

    function<bool(ll)> check = [&](ll val) -> bool{
        vector<vector<ll>> d(n, vector<ll>(n, -INF));
        for (int i = 0; i < n; i++){
            for (int j = 0; j < n; j++){
                if (i == j) continue;
                d[i][j] = max_diff[i][j] - val * dist[i][j];
                if (d[i][j] < 0) d[i][j] = -INF;
            }
            d[i][i] = 0;
        }

        for (int k = 0; k < n; k++){
            for (int i = 0; i < n; i++){
                for (int j = 0; j < n; j++){
                    d[i][j] = max(d[i][j], d[i][k] + d[k][j]);
                }
            }
        }

        for (int i = 0; i < n; i++){
            for (int j = 0; j < n; j++){
                if (i == j) continue;

                ll cur = d[i][j] + max_diff[j][i] - val * dist[j][i];
                if (cur >= 0) return true;
            }
        }

        return false;
    };

    ll l = 0, r = 1e9;
    while (l <= r){
        ll mid = (l + r) >> 1;
        if (check(mid)){
            l = mid + 1;
        } else {
            r = mid - 1;
        }
    }

    cout << l - 1 << endl;

}

int main(){
    clock_t startTime = clock();
    ios_base::sync_with_stdio(false);

#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    int test_cases = 1;
//    cin >> test_cases;

    for (int test = 1; test <= test_cases; test++){
        // cout << (solve() ? "YES" : "NO") << endl;
        solve();
    }

#ifdef LOCAL
    cerr << "Time: " << int((double) (clock() - startTime) / CLOCKS_PER_SEC * 1000) << " ms" << endl;
#endif

    return 0;
}

Compilation message (stderr)

merchant.cpp: In function 'int main()':
merchant.cpp:106:13: warning: unused variable 'startTime' [-Wunused-variable]
  106 |     clock_t startTime = clock();
      |             ^~~~~~~~~

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