oj.uz

Submission #865998

# Submission time Handle Problem Language Result Execution time Memory
865998 2023-10-25T09:25:32 Z mychecksedad Parking (CEOI22_parking) C++17
20 / 100
 243 ms 124196 KB 
/* 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 = 52, MX = 30;


int n, m;
array<int, 2> A[N];
vector<array<int, 2>> B[N], g[N][2];
vector<array<int, 2>> in, vis;
vector<pair<int, int>> ans;
vector<int> v[N];
vector<int> E;
void move(int x, int y){
  if(x == y) return;
  ans.pb({x, y});
  v[y].pb(v[x].back());
  v[x].pop_back();
  if(v[x].empty()) E.pb(x);
}

void solve(){
  cin >> n >> m;
  for(int i = 1; i <= m; ++i){
    cin >> A[i][0] >> A[i][1];
    B[A[i][0]].pb({i, 0});
    B[A[i][1]].pb({i, 1});
    if(A[i][0]) v[i].pb(A[i][0]);
    if(A[i][1]) v[i].pb(A[i][1]);
    if(A[i][0] == 0) E.pb(i);
  }
  for(int i = 1; i <= n; ++i){
    if(B[i][0][0] != B[i][1][0]){
      if(B[i][1][1] == 0) swap(B[i][0], B[i][1]);
      if(B[i][0][1] != B[i][1][1])
        g[B[i][0][0]][B[i][0][1]].pb(B[i][1]);
    }
  }
  for(int i = 1; i <= m; ++i){
    if(A[i][0] != 0 && A[i][1] != 0){
      g[i][1].pb({i, 0});
    }
  }
  in.resize(m+1);
  vis.resize(m+1);
  for(int i = 1; i <= m; ++i){
    for(auto x: g[i][0])
      in[x[0]][x[1]]++;
    for(auto x: g[i][1])
      in[x[0]][x[1]]++;
  }
  queue<array<int, 2>> q;
  for(int i = 1; i <= m; ++i){
    if(in[i][0] == 0) q.push({i, 0}), vis[i][0] = 1;
    if(in[i][1] == 0) q.push({i, 1}), vis[i][1] = 1;
  }

  while(!q.empty()){
    auto x = q.front(); q.pop();
    // cout << x[0] << ' ' << x[1] << endl;
    for(auto u: g[x[0]][x[1]]){
      in[u[0]][u[1]]--;
      if(in[u[0]][u[1]] == 0){
        if(v[u[0]].size() > u[1] && v[x[0]].size() > x[1] && v[u[0]][u[1]] == v[x[0]][x[1]]){
          if(v[x[0]].size() < 2)
          move(u[0], x[0]);
        }
        q.push(u);  
        vis[u[0]][u[1]] = 1;
      }
    }
  }
  // cout << "g" << endl;
  for(int i = 1; i <= n; ++i) B[i].clear(); 
  for(int i = 1; i <= m; ++i){
    if(v[i].size() >= 1) B[v[i][0]].pb({i, 0});
    if(v[i].size() == 2) B[v[i][1]].pb({i, 1});
  }
  for(int i = 1; i <= n; ++i){
    if(B[i][0][0] != B[i][1][0]){
      if(B[i][0][1] == 0 && B[i][1][1] == 0){
        if(v[B[i][0][0]].size() == 1 && v[B[i][1][0]].size() == 1)
          move(B[i][0][0], B[i][1][0]);
      }
    }
  }
// en;
//    cout << ans.size() << '\n';
//   for(auto x: ans) cout << x.first << ' ' << x.second << '\n';
//   en;

  if(!E.empty()){
    for(int i = 1; i <= n; ++i) B[i].clear(); 
    for(int i = 1; i <= m; ++i) g[i][0].clear(), g[i][1].clear(); 
    for(int i = 1; i <= m; ++i){
      if(v[i].size() >= 1) B[v[i][0]].pb({i, 0});
      if(v[i].size() == 2) B[v[i][1]].pb({i, 1});
    }
    for(int i = 1; i <= n; ++i){
      if(B[i][0][0] != B[i][1][0]){
        if(B[i][1][1] == 0) swap(B[i][0], B[i][1]);
        if(B[i][0][1] != B[i][1][1])
          g[B[i][0][0]][B[i][0][1]].pb(B[i][1]);
      }
    }
    for(int i = 1; i <= m; ++i){
      if(v[i].size() == 2){
        g[i][1].pb({i, 0});
      }
    }
    vis.clear();
    vis.resize(m + 1);
    // cout << "zort";
    for(int i = 1; i <= m; ++i){
      if(!vis[i][0]){
        vector<array<int, 2>> st;
        array<int, 2> x = {i, 0};
        st.pb(x);
        while(!vis[x[0]][x[1]]){
          vis[x[0]][x[1]] = 1;
          if(g[x[0]][x[1]].empty()) break;
          x = g[x[0]][x[1]][0];
          st.pb(x);
        }
        if(st.front() == st.back() && st.size() > 1){
          int pos = E.back();
          E.pop_back();
          move(st[0][0], pos);
          st[st.size() - 2][0] = pos;
          for(int i = 1; i < st.size() - 1; i += 2){
            move(st[i][0], st[i - 1][0]);
          }
        }
      }
    }


    for(int i = 1; i <= n; ++i) B[i].clear(); 
    for(int i = 1; i <= m; ++i) g[i][0].clear(), g[i][1].clear(); 
    for(int i = 1; i <= m; ++i){
      if(v[i].size() >= 1) B[v[i][0]].pb({i, 0});
      if(v[i].size() == 2) B[v[i][1]].pb({i, 1});
    }
    for(int i = 1; i <= n; ++i){
      if(B[i][0][0] != B[i][1][0]){
        if(B[i][1][1] == 0) swap(B[i][0], B[i][1]);
        g[B[i][0][0]][B[i][0][1]].pb(B[i][1]);
      }
    }
    for(int i = 1; i <= m; ++i){
      if(v[i].size() == 2){
        g[i][1].pb({i, 0});
      }
    }

    in.clear();
    in.resize(m+1);
    vis.clear();
    vis.resize(m+1);

    for(int i = 1; i <= m; ++i){
      for(auto x: g[i][0])
        in[x[0]][x[1]]++;
      for(auto x: g[i][1])
        in[x[0]][x[1]]++;
    }


    priority_queue<array<int, 3>> q;
    int cur = 1;
    for(int i = 1; i <= m; ++i){
      if(in[i][0] == 0) q.push({-1, i, 0}), vis[i][0] = 1;
      if(in[i][1] == 0) q.push({-1, i, 1}), vis[i][1] = 1;
    }

  //   cout << ans.size() << '\n';
  // for(auto x: ans) cout << x.first << ' ' << x.second << '\n';
  //   cout << "uwu\n\n";

    while(!q.empty()){
      auto y = q.top(); q.pop();
      // cout << x[0] << ' ' << x[1] << endl;
      array<int, 2> x = {y[1], y[2]};
      if(y[0] == -1) ++cur;
      for(auto u: g[x[0]][x[1]]){
        in[u[0]][u[1]]--;
        if(in[u[0]][u[1]] == 0){
          if(v[u[0]].size() > u[1] && v[x[0]].size() > x[1] && v[u[0]][u[1]] == v[x[0]][x[1]] && u[0] != x[0]){
            if(v[u[0]].size() == 2 && v[x[0]].size() == 2){
              if(!E.empty()){
                // cout << u[0] << ' ' << x[0] << ' ' << E.back() << '\n';
                int pos = E.back(); E.pop_back();
                move(u[0], pos);
                move(x[0], pos);
              }else{
                cout << -1;
                return;
              }
            }else
              move(u[0], x[0]);
          }
          q.push({cur, u[0], u[1]});  
          vis[u[0]][u[1]] = 1;
        }
      }
    }
    for(int i = 1; i <= n; ++i) B[i].clear(); 
    for(int i = 1; i <= m; ++i){
      if(v[i].size() >= 1) B[v[i][0]].pb({i, 0});
      if(v[i].size() == 2) B[v[i][1]].pb({i, 1});
    }
    for(int i = 1; i <= n; ++i){
      if(B[i][0][0] != B[i][1][0]){
        if(B[i][0][1] == 0 && B[i][1][1] == 0){
          if(v[B[i][0][0]].size() == 1 && v[B[i][1][0]].size() == 1)
            move(B[i][0][0], B[i][1][0]);
        }
      }
    }
  }

  bool ok = 1;
  for(int i = 1; i <= m; ++i){
    if(v[i].size() == 1) ok = 0;
    else if(v[i].size() == 2) ok &= v[i][0] == v[i][1];
  }
  if(!ok){
    cout << -1;
    return;
  }
  // en;en;en;


  cout << ans.size() << '\n';
  for(auto x: ans) cout << x.first << ' ' << x.second << '\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);
  while(tt--){
    solve();
  }
  cerr<<"time taken : "<<(float)clock()/CLOCKS_PER_SEC<<" seconds\n";
  return 0;
}

Compilation message

Main.cpp: In function 'void solve()':
Main.cpp:70:27: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'std::array<int, 2>::value_type' {aka 'int'} [-Wsign-compare]
   70 |         if(v[u[0]].size() > u[1] && v[x[0]].size() > x[1] && v[u[0]][u[1]] == v[x[0]][x[1]]){
Main.cpp:70:52: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'std::array<int, 2>::value_type' {aka 'int'} [-Wsign-compare]
   70 |         if(v[u[0]].size() > u[1] && v[x[0]].size() > x[1] && v[u[0]][u[1]] == v[x[0]][x[1]]){
Main.cpp:136:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 2> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  136 |           for(int i = 1; i < st.size() - 1; i += 2){
      |                          ~~^~~~~~~~~~~~~~~
Main.cpp:194:29: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'std::array<int, 2>::value_type' {aka 'int'} [-Wsign-compare]
  194 |           if(v[u[0]].size() > u[1] && v[x[0]].size() > x[1] && v[u[0]][u[1]] == v[x[0]][x[1]] && u[0] != x[0]){
Main.cpp:194:54: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'std::array<int, 2>::value_type' {aka 'int'} [-Wsign-compare]
  194 |           if(v[u[0]].size() > u[1] && v[x[0]].size() > x[1] && v[u[0]][u[1]] == v[x[0]][x[1]] && u[0] != x[0]){
Main.cpp: In function 'int main()':
Main.cpp:247:15: warning: unused variable 'aa' [-Wunused-variable]
  247 |   int tt = 1, aa;
      |               ^~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 20 ms 94808 KB Output is correct
2 Correct 20 ms 94812 KB Output is correct
3 Correct 21 ms 94812 KB Output is correct
4 Correct 20 ms 94812 KB Output is correct
5 Correct 19 ms 94812 KB Output is correct
6 Correct 19 ms 94812 KB Output is correct
7 Correct 23 ms 95232 KB Output is correct
8 Correct 20 ms 94812 KB Output is correct
9 Correct 19 ms 94808 KB Output is correct
10 Correct 19 ms 94808 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 205 ms 121332 KB Output is correct
2 Correct 243 ms 124196 KB Output is correct
3 Correct 184 ms 123036 KB Output is correct
4 Correct 184 ms 122296 KB Output is correct
5 Correct 228 ms 124148 KB Output is correct

Subtask #3
0.0 / 25.0

# Verdict Execution time Memory Grader output
1 Incorrect 20 ms 95068 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0.0 / 15.0

# Verdict Execution time Memory Grader output
1 Incorrect 20 ms 95068 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #5
0.0 / 25.0

# Verdict Execution time Memory Grader output
1 Incorrect 21 ms 95068 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #6
0.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 20 ms 94808 KB Output is correct
2 Correct 20 ms 94812 KB Output is correct
3 Correct 21 ms 94812 KB Output is correct
4 Correct 20 ms 94812 KB Output is correct
5 Correct 19 ms 94812 KB Output is correct
6 Correct 19 ms 94812 KB Output is correct
7 Correct 23 ms 95232 KB Output is correct
8 Correct 20 ms 94812 KB Output is correct
9 Correct 19 ms 94808 KB Output is correct
10 Correct 19 ms 94808 KB Output is correct
11 Correct 205 ms 121332 KB Output is correct
12 Correct 243 ms 124196 KB Output is correct
13 Correct 184 ms 123036 KB Output is correct
14 Correct 184 ms 122296 KB Output is correct
15 Correct 228 ms 124148 KB Output is correct
16 Incorrect 20 ms 95068 KB Output isn't correct
17 Halted 0 ms 0 KB -