Submission #511221

#	Time	Username	Problem	Language	Result	Execution time	Memory
511221		600Mihnea	Salesman (IOI09_salesman)	C++17	32 / 100	3089 ms	37484 KiB

salesman

#include <bits/stdc++.h>

using namespace std;

const int N = (int) 5e5 + 7;
const int INF = (int) 1e9 + 7;
int n;
int add;
int t[N];
int x[N];
int g[N];
int dp[N];
int pref[N];

signed main() {
  ios::sync_with_stdio(0); cin.tie(0);

///  freopen ("input", "r", stdin);

  cin >> n;
  {
    int cost1, cost2;
    cin >> cost1 >> cost2;
    add = -(cost1 + cost2);
    cin >> x[0];
    x[n + 1] = x[0];
    t[n + 1] = (int) 5e5 + 3;
  }

  for (int i = 1; i <= n; i++) {
    cin >> t[i] >> x[i] >> g[i];
    g[i] *= 2;
  }

  vector<vector<int>> guys;
  for (int i = 0; i <= n + 1; i++) {
    guys.push_back({t[i], x[i], i});
  }
  sort(guys.begin(), guys.end());
  int current = 0;
  for (int i = 0; i < (int) guys.size(); i++) {
    current += g[guys[i][2]];
    pref[i] = current;
  }
  for (int i = 0; i <= n + 1; i++) {
    x[i] = guys[i][1];
  }
  for (int i = 1; i <= n + 1; i++) {
    dp[i] = -INF;
  }
  {
    int l = 0;
    while (l < (int) guys.size()) {
      int r = l;
      while (r + 1 < (int) guys.size() && guys[r + 1][0] == guys[r][0]) {
        r++;
      }
      for (int i = 0; i < l; i++) {
        for (int j = l; j <= r; j++) {
          for (int k = j; k <= r; k++) {
            dp[j] = max(dp[j], dp[i] + (abs(x[i] - x[k]) + x[k] - x[j]) * add + pref[k] - pref[j - 1]);
          }
        }
        for (int j = l; j <= r; j++) {
          for (int k = l; k < j; k++) {
            int total_gain = pref[max(j, k)] - pref[min(j, k) - 1];
            dp[j] = max(dp[j], dp[i] + (abs(x[i] - x[k]) + x[j] - x[k]) * add + pref[j] - pref[k - 1]);
          }
        }
      }
      l = r + 1;
    }
  }
  cout << dp[n + 1] / 2 << "\n";


  return 0;
}

Compilation message (stderr)

salesman.cpp: In function 'int main()':
salesman.cpp:66:17: warning: unused variable 'total_gain' [-Wunused-variable]
   66 |             int total_gain = pref[max(j, k)] - pref[min(j, k) - 1];
      |                 ^~~~~~~~~~

• Subtask 1: 32 / 100