Submission #417554

#	Time	Username	Problem	Language	Result	Execution time	Memory
417554		pauloamed	Bitaro’s Party (JOI18_bitaro)	C++14	100 / 100	1557 ms	119948 KiB

bitaro

#include<bits/stdc++.h>
using namespace std;

#define MAXN 100010
#define BLOCK 100
#define ppiii pair<pair<int,int>,int>

int n;
vector<int> v[MAXN];
vector<int> rv[MAXN];

int fullSolution(int x, vector<bool> &on){
  vector<int> pd(x+1, -1);

  int ans = -1;
  pd[x] = 0;
  for(int i = x; i >= 0; --i){
    if(pd[i] != -1){
      for(auto y : rv[i]){
          pd[y] = max(pd[y], pd[i] + 1);
      }
    }
    if(on[i]) ans = max(ans, pd[i]);
  }
  return ans;
}


int main(){
  int m, q; scanf("%d %d %d", &n, &m, &q);
  for(int i = 0; i < m; ++i){
    int a, b;  scanf("%d %d", &a, &b);; a--, b--;
    if(a > b) swap(a, b);
    v[a].push_back(b);
    rv[b].push_back(a);
  }

  // int block = max(1, ((int)sqrt(n)));
  // cout << block << endl;

  vector<vector<pair<int,int>>> bestDists(n);

  vector<bool> occour(n);
  for(int i = 0; i < n; ++i){
    vector<int> currPointers(rv[i].size());

    priority_queue<ppiii, vector<ppiii>, less<ppiii>> pq;
    for(int j = 0; j < rv[i].size(); ++j){
      pq.push(make_pair(bestDists[rv[i][j]].front(), j));
    }

    while(pq.size() && bestDists[i].size() < BLOCK){
      auto x = pq.top();
      int j = x.second;
      int id = x.first.second;
      pq.pop();

      if(++currPointers[j] < bestDists[rv[i][j]].size()){
        pq.push(make_pair(bestDists[rv[i][j]][currPointers[j]], j));
      }

      if(!occour[id]){
        occour[id] = true;
        bestDists[i].push_back(x.first);
      }
    }

    for(auto &x : bestDists[i]) x.first++;
    if(bestDists[i].size() < BLOCK) bestDists[i].push_back({0, i});
    for(auto x : bestDists[i]) occour[x.second] = false;
  }

  vector<bool> on(n, true);
  while(q--){
    int x, y; scanf("%d %d", &x, &y); x--;
    vector<int> currOff;

    int before = 0;
    while(y--){
      int z; scanf("%d", &z); z--;
      on[z] = false;
      currOff.push_back(z);
      if(z <= x) before++;
    }

    int ans = -1;
    for(auto z : bestDists[x]){
      if(on[z.second]){
        ans = z.first; break;
      }
    }

    if(before <= x && ans == -1) ans = fullSolution(x, on);
    printf("%d\n", ans);
    for(auto z : currOff) on[z] = true;
  }
}

Compilation message (stderr)

bitaro.cpp: In function 'int main()':
bitaro.cpp:48:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |     for(int j = 0; j < rv[i].size(); ++j){
      |                    ~~^~~~~~~~~~~~~~
bitaro.cpp:58:28: warning: comparison of integer expressions of different signedness: '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'} and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |       if(++currPointers[j] < bestDists[rv[i][j]].size()){
      |          ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
bitaro.cpp:30:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |   int m, q; scanf("%d %d %d", &n, &m, &q);
      |             ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
bitaro.cpp:32:21: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |     int a, b;  scanf("%d %d", &a, &b);; a--, b--;
      |                ~~~~~^~~~~~~~~~~~~~~~~
bitaro.cpp:75:20: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   75 |     int x, y; scanf("%d %d", &x, &y); x--;
      |               ~~~~~^~~~~~~~~~~~~~~~~
bitaro.cpp:80:19: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   80 |       int z; scanf("%d", &z); z--;
      |              ~~~~~^~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 7 / 7
• Subtask 3: 86 / 86