Submission #283539

#	Time	Username	Problem	Language	Result	Execution time	Memory
283539		ipaljak	Arranging Shoes (IOI19_shoes)	C++14	50 / 100	311 ms	53112 KiB

shoes

#include "shoes.h"

#include <bits/stdc++.h>

using namespace std;

#define TRACE(x) cerr << #x << " " << x << endl
#define _ << " " <<

typedef long long llint;

const int MAXN = 1e5 + 5;

bool bio[MAXN];

int n;
int nxt[2 * MAXN], loga[2 * MAXN];

vector<int> s;

void init() {
  memset(nxt, -1, sizeof nxt);
  map<int, vector<int>> m;
  for (int i = 0; i < n; ++i)
    m[s[i]].push_back(i);
  for (auto &p : m) {
    assert(p.second.size() == m[-p.first].size());
    for (int i = 0; i < (int) p.second.size(); ++i) {
      nxt[p.second[i]] = m[-p.first][i];
      nxt[m[-p.first][i]] = p.second[i];
    }
  }
}

void add(int i) {
  for (; i < 2 * MAXN; i += i & -i) loga[i]++;
}

int sum(int lo, int hi) {
  int ret = 0;
  for (; hi > 0; hi -= hi & -hi) ret += loga[hi];
  for (--lo; lo > 0; lo -= lo & -lo) ret -= loga[lo];
  return ret;
}

llint count_swaps(vector<int> _s) {
  s = _s;
  n = (int) s.size();
  init();

  llint sol = 0;
  for (int i = 0; i < n; ++i) {
    if (bio[i]) continue;
    assert(nxt[i] > i);
    int l = i, r = nxt[i];
    bio[l] = bio[r] = true;
    sol += (llint) r - l - 1;
    sol -= sum(l + 1, r + 1);
    add(l + 1);
    add(r + 1);
    if (s[i] > 0) ++sol;
  }

	return sol;
}

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