Submission #1032300

#	Time	Username	Problem	Language	Result	Execution time	Memory
1032300		Tonyl	Fun Tour (APIO20_fun)	C++17	47 / 100	165 ms	16460 KiB

fun

#include "fun.h"
#include <bits/stdc++.h>
using namespace std;
using vi = vector<int>;
using pi = pair<int,int>;
using ll = long long;
#define REP(i,n) for (int i = 0; i < n; i++)
#define trav(a,x) for (auto &a : x)
#define all(x) (x).begin(), (x).end()
#define D(x) cerr << #x << ": " << x << endl;

int n, q;

map<pi, int> dists;
int ask_dist(int a, int b) {
  if (a > b) swap(a,b);
  if (!dists.count({a,b})) dists[{a,b}] = hoursRequired(a,b);
  return dists[{a,b}];
}
//attractionsBehind

std::vector<int> createFunTour500(int N, int Q) {
  n = N; q = Q;
  vector<pair<int,pi>> alld(n*n);
  REP(i,n) {
    REP(j,n) alld[i*n+j] = {ask_dist(i,j), {i,j}};
  }
  sort(all(alld));

  vector<bool> done(n, 0);
  int s = alld.back().second.first;
  vi ans = {s};
  done[s] = 1;
  //D(s);

  while (--n) {
    int best = s;
    REP(i,N) {
      if (done[i]) continue;
      if (ask_dist(s, best) < ask_dist(s, i)) best = i;
    }
    assert(s != best);
    s = best;
    //D(s);
    done[s] = 1;
    ans.push_back(s);
  }

  return ans;
}

struct Node {
  bool exists = false;
  int leftd = 0, rightd = 0;
};

const int MAX_N = 400004;
Node tree[MAX_N];

void update(int i) {
  tree[i].leftd = 0;
  if (tree[2*i].exists) tree[i].leftd = max(tree[2*i].leftd, tree[2*i].rightd) + 1;
  tree[i].rightd = 0;
  if (tree[2*i+1].exists) tree[i].rightd = max(tree[2*i+1].leftd, tree[2*i+1].rightd) + 1;

  if (i > 1) update(i/2);
}

void consume(int i) {
  assert(tree[i].exists);
  tree[i].exists = 0;
  update(i);
}

int sink(int i) {
  if (tree[i].leftd > tree[i].rightd) return sink(2*i);
  else if (tree[i].rightd == 0) return i;
  else return sink(2*i+1);
}

int find_best(int i) {
  int best = 2*i+1;
  bool just_top = false;

  if (tree[i].leftd >= tree[i].rightd) best = 2*i;
  int maxs = max(tree[i].leftd, tree[i].rightd);

  int bonus = 0;
  while (i > 1) {
    bool fr = i%2;
    i/=2;
    bonus++;
    if (!tree[i].exists) break;
    if (bonus > maxs) {
      best = i; maxs = bonus;
      just_top = 1;
    }
    if (fr) {
      if (bonus+tree[i].leftd > maxs) {
        best = 2*i;
        maxs = bonus+tree[i].leftd;
        just_top = 0;
      }
    } else {
      if (bonus+tree[i].rightd > maxs) {
        best = 2*i+1;
        maxs = bonus+tree[i].rightd;
        just_top = 0;
      }
    }
  }

  if (just_top) return best;
  else return sink(best);
}

std::vector<int> createFunTour(int N, int Q) {
  if (N <= 500) return createFunTour500(N, Q);

  n = N; q = Q;
  n++;
  
  REP(i,n) tree[i].exists = 1;
  REP(i,n) update(i);

  int s = n-1;
  vi ans = {s};
  consume(s);
  //D(s);

  while (--N) {
    s = find_best(s);
    //D(s);
    consume(s);
    ans.push_back(s);
  }

  REP(i,n) ans[i]--;
  return ans;
}

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