Submission #845397

#	Time	Username	Problem	Language	Result	Execution time	Memory
845397		vjudge1	Skandi (COCI20_skandi)	C++17	0 / 110	13 ms	55388 KiB

Main

/* Author : Mychecksdead  */
#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define pb push_back
#define all(x) x.begin(), x.end()
#define en cout << '\n'
const int N = 1e6+100, M = 1e5+10, K = 18;



int n, m;
string s[N];
vector<int> g[N];
vector<pair<int, int>> segdown;
vector<pair<int, int>> segright;
vector<bool> vis(N);
vector<int> white;
vector<int> nigga;

pair<int, int> dfs(int v, bool col){
  if(v <= n*m && v > segdown.size()) return {0, 0};
  if(v > n*m && v > segright.size()+n*m) return {0, 0};

  vis[v] = 1;
  if(col){
    white.pb(v);
  }else{
    nigga.pb(v);
  }
  pair<int, int> dpv = {1, 0};
  bool taken = 0;
  for(int u: g[v]){
    if(!vis[u]){
      auto dpu = dfs(u, col^1);
      dpv.first += min(dpu.first, dpu.second);
      dpv.second += dpu.first;
      taken = 1;
    }
  }
  if(!taken) dpv.second = 1;
  return dpv;
}

void solve(){
  cin >> n >> m;
  for(int i = 0; i < n; ++i) cin >> s[i];
  
  vector<vector<vector<int>>> c(n);
  for(int i = 0; i < n; ++i) c[i].resize(m);

  for(int i = 0; i < n; ++i){
    for(int j = 0; j < m; ++j){
      if(s[i][j] == '0' && s[i - 1][j] == '1'){
        int idx = segdown.size() + 1;
        for(int k = i; k < n; ++k){
          if(s[k][j] == '1') break;
          c[k][j].pb(idx);
        }
        segdown.pb({i, j});
      }
      if(s[i][j] == '0' && s[i][j - 1] == '1'){
        int idx = n*m+segright.size()+1;
        for(int k = j; k < m; ++k){
          if(s[i][k] == '1') break;
          c[i][k].pb(idx);
        }
        segright.pb({i, j});
      }
    }
  }
  for(int i = 0; i < n; ++i){
    for(int j = 0; j < m; ++j){
      if(s[i][j] == '0'){
        g[c[i][j][0]].pb(c[i][j][1]);
        g[c[i][j][1]].pb(c[i][j][0]);
      }
    }
  }
  int ans = 0;
  for(int i = 1; i <= 2*n*m; ++i){
    if(!vis[i]){
      pair<int, int> dpv = dfs(i, 0);
      ans += min(dpv.first, dpv.second);
    }
  }
  cout << ans;
  return;
  if(white.size() > nigga.size()) white.swap(nigga);
  cout << white.size() << '\n';
  for(auto w: white){
    if(w >= n*m){
      cout << segright[w - n*m - 1].first + 1 << ' ' << segright[w - n*m - 1].second << ' '<< "DESNO\n";
    }else{
      cout << segdown[w - 1].first << ' ' << segdown[w - 1].second + 1 << ' '<< "DOLJE\n";
    }
  }
}


int main(){
  cin.tie(0); ios::sync_with_stdio(0);
  int tt = 1, aa;
  // freopen("in.txt", "r", stdin);
  // freopen("out.txt", "w", stdout);
  // cin >> tt;
  while(tt--){
    solve();
    // en;
  }
  cerr<<"time taken : "<<(float)clock()/CLOCKS_PER_SEC<<" seconds\n";
  return 0;
}

Compilation message (stderr)

skandi.cpp: In function 'std::pair<int, int> dfs(int, bool)':
skandi.cpp:24:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   24 |   if(v <= n*m && v > segdown.size()) return {0, 0};
      |                  ~~^~~~~~~~~~~~~~~~
skandi.cpp:25:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |   if(v > n*m && v > segright.size()+n*m) return {0, 0};
      |                 ~~^~~~~~~~~~~~~~~~~~~~~
skandi.cpp: In function 'int main()':
skandi.cpp:105:15: warning: unused variable 'aa' [-Wunused-variable]
  105 |   int tt = 1, aa;
      |               ^~

• Subtask 1: 0 / 18
• Subtask 2: 0 / 32
• Subtask 3: 0 / 60