Submission #234144

#	Time	Username	Problem	Language	Result	Execution time	Memory
234144		rama_pang	Travelling Merchant (APIO17_merchant)	C++14	100 / 100	178 ms	3448 KiB

merchant

#include <bits/stdc++.h>
using namespace std;

const long long inf = 1e18;

int N, M, K;
int B[105][1005];
int S[105][1005];

int dist[105][105];
int profit[105][105];

void Read() {
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);

  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 j = 1; j <= N; j++) {
      dist[i][j] = 1e9 + 100;
    }
  }
  for (int i = 0; i < M; i++) {
    int u, v, t;
    cin >> u >> v >> t;
    dist[u][v] = t;
  }
}

void FloydWarshall() {
  for (int k = 1; k <= N; k++) {
    for (int i = 1; i <= N; i++) {
      for (int j = 1; j <= N; j++) {
        if (dist[i][j] > dist[i][k] + dist[k][j]) {
          dist[i][j] = dist[i][k] + dist[k][j];
        }
      }
    }
  }
  for (int k = 1; k <= K; k++) {
    for (int i = 1; i <= N; i++) {
      for (int j = 1; j <= N; j++) {
        if (S[j][k] == -1 || B[i][k] == -1) continue;
        profit[i][j] = max(profit[i][j], S[j][k] - B[i][k]);
      }
    }
  }
}

bool Check(int r) {
  // profit / dist >= r -> profit - r * dist >= 0
  long long chk[105][105];
  for (int i = 1; i <= N; i++) {
    for (int j = 1; j <= N; j++) {
      if (i == j) {
        chk[i][j] = -inf;
      } else {
        chk[i][j] = max(-inf, 1ll * profit[i][j] - 1ll * r * dist[i][j]);
      }
    }
  }
  for (int rep = 0; rep < 2; rep++) {
    for (int k = 1; k <= N; k++) {
      for (int i = 1; i <= N; i++) {
        for (int j = 1; j <= N; j++) {
          if (chk[i][j] < chk[i][k] + chk[k][j]) {
            chk[i][j] = min(inf, chk[i][k] + chk[k][j]);
          }
          if (chk[j][j] >= 0) {
            return true;
          }
        }
      }
    }
  }
  return false;
}

int main() {
  Read();
  FloydWarshall();
  
  int lo = 0, hi = 1e9 + 100;
  while (lo < hi) {
    int mid = (lo + hi + 1) / 2;
    if (Check(mid)) {
      lo = mid;
    } else {
      hi = mid -1;
    }
  }

  cout << lo << "\n";
  return 0;
}

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