Submission #932702

#	Time	Username	Problem	Language	Result	Execution time	Memory
932702		nguyentunglam	Permutation (APIO22_perm)	C++17	100 / 100	6 ms	460 KiB

perm

#include<bits/stdc++.h>
#define fi first
#define se second
#define endl "\n"
#define ii pair<int, int>
using namespace std;

const long long inf = 2e18;

long long calc (vector<int> a) {
  vector<long long> f(a.size());
  long long ret = 1;
  for(int i = 0; i < a.size(); i++) {
    f[i] = 1;
    for(int j = 0; j < i; j++) if (a[j] < a[i]) f[i] = min(inf, f[i] + f[j]);
    ret += f[i];
  }
  return ret;
}

vector<int> get (vector<int> p) {
  vector<int> rrh = p;

  sort(rrh.begin(), rrh.end());
  rrh.resize(unique(rrh.begin(), rrh.end()) - rrh.begin());
  auto get = [&] (int x) {
    return lower_bound(rrh.begin(), rrh.end(), x) - rrh.begin();
  };

  for(auto &j : p) j = get(j);
  return p;
}

vector<int> construct_permutation(long long k) {
  vector<int> a;
  while (k >= 4) {
    a.push_back(k % 4);
    k /= 4;
  }
  reverse(a.begin(), a.end());
  vector<int> p;
  if (k == 2) p = {0};
  if (k == 3) p = {1, 0};
  for(int &j : a) {
    int mx = p.size();
    if (j == 0) {
      p.push_back(mx);
      p.push_back(mx + 1);
    }
    if (j == 1) {
      p.push_back(mx);
      p.push_back(mx + 1);
      p.push_back(-1);
    }
    if (j == 2) {
      p.push_back(mx);
      p.push_back(-1);
      p.push_back(mx + 1);
    }
    if (j == 3) {
      int x = -1;
      for(auto &j : p) if (j == 0 || j == 1) {
        x = j;
        break;
      }
      if (p.size() >= 2 && x == 1) {
        p.push_back(mx);
        p.push_back(mx + 1);
        for(int &j : p) if (j >= 2) j++;
        p.push_back(2);
      }
      else {
        p.push_back(mx);
        p.push_back(-1);
        p.push_back(mx + 1);
        p.push_back(-2);
      }
    }
    p = get(p);
  }
  return p;
}

#ifdef ngu
int main() {

  freopen ("task.inp", "r", stdin);
  freopen ("task.out", "w", stdout);

  long long k; cin >> k;

  vector<int> ans = construct_permutation(k);
  for(int &j : ans) cout << j << " "; cout << endl;
  cerr << ans.size() << endl;
  assert(calc(ans) == k);
}
#endif // ngu

Compilation message (stderr)

perm.cpp: In function 'long long int calc(std::vector<int>)':
perm.cpp:13:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   13 |   for(int i = 0; i < a.size(); i++) {
      |                  ~~^~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 90 / 90