Submission #1182363

#	Time	Username	Problem	Language	Result	Execution time	Memory
1182363		zaki98	Cave (IOI13_cave)	C++20	64 / 100	670 ms	712 KiB

cave

#include <bits/stdc++.h>
#define vt vector
#define sz(c) (c).size()
using namespace std;
#include "cave.h"

vt<int> vS, vD, vDs;

int tryC(vt<int> arr){
  const int x = sz(arr);
  int S[x];
  for (int i=0;i<x;i++) S[i] = arr[i];
  int ans = tryCombination(S);
  return (ans== -1 ? x : ans);
}

vt<int> special(int x, int type, int n){
  vt<int> res(n);
  for (int i=0;i<n;i++){
    if (i < x) res[i] = type;
    else res[i] = !type;
  }
  return res;
}


// log (n)
int find_door(vt<int>ind, int door, int type){
  vt<int> copy = vS;
  int n = sz(vS);

  int len = count_if(ind.begin(), ind.end(), [](int x){ return x != -1; });
  int l=0,r=len-1;
  while(l<r){
    int m = l + (r-l+1)/2;
    vt<int> x = special(m, type, len);
    int cur=0;
    for (int i=0;i<n;i++){
      if (ind[i] != -1 && cur < x.size() && ind[i] < copy.size()) {copy[ind[i]] = x[cur];cur++;}  
    }
    int ans = tryC(copy);
    if (ans <= door){
      l = m;
    } else {
      r = m-1;
    }
  }
  int cur=0,res=0;
  for (int i=0;i<n;i++){
    if (cur == l && ind[i] != -1) break;
    if (ind[i] != -1) cur++;
    res++;
  }
  // cout << "finding door" << door << " of type " << type;
  // cout << " for indices :"; 
  // for (int i=0;i<n;i++) if (ind[i]!=-1) cout << ind[i] << " "; cout << ", ";
  // cout << "answer is :" << res << endl;
  return res;
};

void exploreCave(int n) {
  int S[n], D[n], Ds[n];
  vS.resize(n);vD.resize(n);vDs.resize(n);
  // Correct state of lever i, door mapped to lever i, state of door i
  for (int i=0;i<n;i++){
    S[i] = 0; vS[i] = 0;
    D[i] = -1; vD[i] = -1;
    Ds[i] = -1; vDs[i] = -1;
  }

  vt<int> ind(n);
  iota(ind.begin(), ind.end(), 0);
  int x = tryC(vS);
  for (int i=0;i<x;i++){
    int f = find_door(ind, i, 0);
    vDs[i] = 0;
    ind[f] = -1;
    vD[f] = i;
    vS[f] = 0;
  }
  if (x < n) {
    int f = find_door(ind, x, 1);
    ind[f] = -1;
    vD[f] = x;
    vDs[x] = 1;
    vS[f] = 1;
  }
  for (int i=x+1;i<n;i++){
    int x = tryC(vS);
    bool type;
    if (x == i) type = 1;
    else type = 0;
    int f = find_door(ind, i, type);
    ind[f] = -1;
    vD[f] = i;
    vDs[x] = type;
    vS[f] = type;
  }

  /* Recover
  for (int i=0;i<n;i++) {
    S[D[i]] = Ds[D[i]];
  }
 */
  for (int i=0;i<n;i++) D[i] = vD[i];
  for (int i=0;i<n;i++) S[i] = vS[i];
  answer(S, D);
}

• Subtask 1: 0 / 12
• Subtask 2: 13 / 13
• Subtask 3: 21 / 21
• Subtask 4: 30 / 30
• Subtask 5: 0 / 24