Submission #898568

#	Time	Username	Problem	Language	Result	Execution time	Memory
898568		OAleksa	Fun Tour (APIO20_fun)	C++14	47 / 100	104 ms	15168 KiB

fun

#include "fun.h"
#include <bits/stdc++.h>
#define f first
#define s second
using namespace std;
vector<int> createFunTour(int N, int Q) {
  int n = N;
  int cen = 0;
  if (n == 2)
    return {0, 1};
  for (int i = 1;i < n;i++) {
    if (attractionsBehind(cen, i) > n / 2)
      cen = i;
  }
  vector<int> dis(n);
  for (int i = 0;i < n;i++) {
    if (i == cen)
      continue;
    dis[i] = hoursRequired(cen, i);
  }
  vector<int> p;
  for (int i = 0;i < n;i++) {
    if (dis[i] == 1) {
      p.push_back(i);
    }
  }
  int m = p.size();
  vector<int> ch[m];
  for (int i = 0;i < n;i++) {
    if (i == cen)
      continue;
    for (int j = 0;j < m;j++) {
      if (j == m - 1) {
        ch[j].push_back(i);
      }
      else {
        int x = hoursRequired(p[j], i);
        if (x + 1 == dis[i]) {
          ch[j].push_back(i);
          break;
        }
      }
    }
  }
  for (int i = 0;i < m;i++) {
    sort(ch[i].begin(), ch[i].end(), [&](int x, int y) {
      return dis[x] < dis[y];
    });
  }
  vector<int> ans;
  auto Resi2 = [&](vector<int> s1, vector<int> s2) {
    if (s1.size() > s2.size())
      swap(s1, s2);
    int lst = 0;
    while (!s2.empty()) {
      if (lst == 0) {
        ans.push_back(s2.back());
        s2.pop_back();
        lst = 1;
      }
      else {
        ans.push_back(s1.back());
        s1.pop_back();
        lst = 0;
      }
    }
    if (!s1.empty()) {
      assert(s1.size() == 1); //jednaki su
      ans.push_back(s1.back());
    }
  };
  if (m == 2) {
    Resi2(ch[0], ch[1]);
  }
  else {
    int lst = -1;
    while (1) {
      int u = 0, mx = 0;
      for (int i = 0;i < m;i++) {
        mx = max(mx, (int)ch[i].size());
        u += ch[i].size();
      }
      if (mx == u - mx && mx > 0)
        break;
      mx = 0;
      int node = -1;
      for (int j = 0;j < m;j++) {
        if (j == lst)
          continue;
        if (dis[ch[j].back()] > mx) {
          mx = dis[ch[j].back()];
          node = j;
        }
      }
      assert(node != -1);
      ans.push_back(ch[node].back());
      ch[node].pop_back();
      lst = node;
    }
    int bst = 0;
    for (int i = 1;i < m;i++) {
      if (ch[i].size() > ch[bst].size())
        bst = i;
    }
    assert(lst != bst);
    vector<int> all;
    for (int i = 0;i < m;i++) {
      if (i == bst)
        continue;
      for (auto u : ch[i])
        all.push_back(u);
    }
    sort(all.begin(), all.end(), [&](int i, int j) {
      return dis[i] < dis[j];
    });
    Resi2(all, ch[bst]);
  }
  ans.push_back(cen);
  return ans;
}
/*
7 400000
0 1
0 5
0 6
1 2
1 4
2 3
*/

• Subtask 1: 10 / 10
• Subtask 2: 16 / 16
• Subtask 3: 21 / 21
• Subtask 4: 0 / 19
• Subtask 5: 0 / 34