Submission #169147

#	Time	Username	Problem	Language	Result	Execution time	Memory
169147		AlexLuchianov	Parachute rings (IOI12_rings)	C++14	0 / 100	4033 ms	11240 KiB

rings

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

using ll = long long;
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
#define MAX(a, b) (((a) < (b)) ? (b) : (a))

int const nmax = 100000;
int N;

vector<int> g[1 + nmax];
vector<pair<int,int>> edge;

namespace Dsu{
  int mult[1 + nmax];
  int sz[1 + nmax];
  void initialize(int n){
    for(int i = 0;i < n; i++) {
      mult[i] = i;
      sz[i] = 1;
    }
  }
  int jump(int a){
    if(mult[a] != a)
      mult[a] = jump(mult[a]);
    return mult[a];
  }
  void unite(int gala, int galb){
    gala = jump(gala);
    galb = jump(galb);
    if(sz[galb] < sz[gala])
      swap(gala, galb);
    if(gala != galb) {
      sz[galb] += sz[gala];
      mult[gala] = galb;
    }
  }
}

vector<int> candidates;
int deg[1 + nmax];

void Init(int N_) {
  N = N_;
  Dsu::initialize(N);
  for(int i = 0; i < N; i++)
    candidates.push_back(i);
}

bool test(int deleted){
  Dsu::initialize(N);
  for(int i = 0;i < N; i++)
    deg[i] = 0;

  for(int i = 0; i < edge.size(); i++){
    int x = edge[i].first;
    int y = edge[i].second;
    if(x != deleted && y != deleted){
      if(deg[x] < 2 && deg[y] < 2 && Dsu::jump(x) != Dsu::jump(y))
        Dsu::unite(x, y);
      else
        return false;
      deg[x]++;
      deg[y]++;
    }
  }
  return true;
}

void clearcandidates(){
  vector<int> newcand;
  for(int i = 0; i < candidates.size(); i++)
    if(test(candidates[i]) == 1)
      newcand.push_back(candidates[i]);
  candidates = newcand;

  Dsu::initialize(N);
  for(int i = 0; i < edge.size(); i++){
    int x = edge[i].first;
    int y = edge[i].second;
    Dsu::unite(x, y);
  }

}

void Link(int a, int b) {
  if(candidates.size() == 0)
    return ;

  if(g[b].size() < g[a].size())
    swap(a, b);

  edge.push_back({a, b});
  g[a].push_back(b);
  g[b].push_back(a);
  clearcandidates();
  return ;
  if(g[a].size() <= 2 && g[b].size() <= 2) {
    if(Dsu::jump(a) == Dsu::jump(b) && Dsu::jump(a) == Dsu::jump(candidates[0]))
      clearcandidates();
    Dsu::unite(a, b);
    return ;
  } else if(candidates.size() == 1 && candidates[0] == b) {
    Dsu::unite(a, b);
    return ;
  } else if(candidates.size() == N){
    candidates.clear();
    for(int i = 0; i < g[a].size(); i++)
      candidates.push_back(g[a][i]);
    for(int i = 0; i < g[b].size(); i++)
      candidates.push_back(g[b][i]);
    sort(candidates.begin(), candidates.end());
    candidates.erase(unique(candidates.begin(), candidates.end()), candidates.end());
    Dsu::unite(a, b);
  }
  clearcandidates();
}

int CountCritical() {
  //std::cout << "result " << candidates.size() << '\n';

  return candidates.size();
}

Compilation message (stderr)

rings.cpp: In function 'bool test(int)':
rings.cpp:58:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i = 0; i < edge.size(); i++){
                  ~~^~~~~~~~~~~~~
rings.cpp: In function 'void clearcandidates()':
rings.cpp:75:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i = 0; i < candidates.size(); i++)
                  ~~^~~~~~~~~~~~~~~~~~~
rings.cpp:81:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i = 0; i < edge.size(); i++){
                  ~~^~~~~~~~~~~~~
rings.cpp: In function 'void Link(int, int)':
rings.cpp:109:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   } else if(candidates.size() == N){
             ~~~~~~~~~~~~~~~~~~^~~~
rings.cpp:111:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < g[a].size(); i++)
                    ~~^~~~~~~~~~~~~
rings.cpp:113:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < g[b].size(); i++)
                    ~~^~~~~~~~~~~~~

• Subtask 1: 0 / 20
• Subtask 2: 0 / 17
• Subtask 3: 0 / 18
• Subtask 4: 0 / 14
• Subtask 5: 0 / 31