Submission #272569

#	Time	Username	Problem	Language	Result	Execution time	Memory
272569		toonewbie	Arranging Shoes (IOI19_shoes)	C++17	100 / 100	353 ms	146988 KiB

shoes

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

using ll = long long;
ll count_swaps(vector<int> S) {
  int N = int(S.size());
  unordered_map<int, queue<int>> unpaired;
  vector<int> bit(N+1);
  ll ans = 0;
  for (int i = 0; i < N; i++) {
    int j;
    if (unpaired[-S[i]].empty()) {
      j = i+1;
      unpaired[S[i]].push(j);
    } else {
      j = unpaired[-S[i]].front(); unpaired[-S[i]].pop();
      ans += i;
      for (int a = j; a; a -= a & (-a)) {
        ans -= bit[a];
      }
      if (S[i] < 0) ans++;
    }
    for (int a = j; a <= N; a += a & (-a)) {
      bit[a]++;
    }
  }
  return ans;
}

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