Submission #208332

#	Time	Username	Problem	Language	Result	Execution time	Memory
208332		alexxela12345	Arranging Shoes (IOI19_shoes)	C++17	50 / 100	1098 ms	24568 KiB

shoes

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

typedef long long ll;

ll count_swaps(vector<int> a) {
  int n = a.size() / 2;
  ll ans = 0;
  map<int, vector<int>> last;
  vector<int> pr(2 * n, -1);
  for (int i = 2 * n - 1; i >= 0; i--) {
    last[a[i]].push_back(i);
  }
  for (int i = 0; i < 2 * n; i++) {
    if (pr[i] != -1)
      continue;
    pr[i] = last[-a[i]].back();;
    last[-a[i]].pop_back();
    last[a[i]].pop_back();
    ans += abs(pr[i] - i) - 1;
    if ((pr[i] > i) != (a[pr[i]] > a[i])) {
      ans++;
    }
    pr[pr[i]] = i;
  }
  for (int i = 0; i < 2 * n; i++) {
    if (pr[i] > i) {
      for (int j = i + 1; j < pr[i]; j++) {
        if (pr[j] > pr[i]) {
          ans--;
        }
      }
    }
  }
  return ans;
}

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 15
• Subtask 5: 20 / 20
• Subtask 6: 0 / 15