oj.uz

Submission #865991

# Submission time Handle Problem Language Result Execution time Memory
865991 2023-10-25T09:13:00 Z mychecksedad Parking (CEOI22_parking) C++17
20 / 100
 179 ms 120512 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]]++;
    }


    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;
    }

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

    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]] && 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(u);  
          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:191:29: 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]
  191 |           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:191:54: 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]
  191 |           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:244:15: warning: unused variable 'aa' [-Wunused-variable]
  244 |   int tt = 1, aa;
      |               ^~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 94808 KB Output is correct
2 Correct 22 ms 95024 KB Output is correct
3 Correct 22 ms 94812 KB Output is correct
4 Correct 21 ms 94812 KB Output is correct
5 Correct 22 ms 95032 KB Output is correct
6 Correct 22 ms 94812 KB Output is correct
7 Correct 21 ms 95116 KB Output is correct
8 Correct 21 ms 95040 KB Output is correct
9 Correct 21 ms 94808 KB Output is correct
10 Correct 20 ms 94812 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 161 ms 118216 KB Output is correct
2 Correct 169 ms 120512 KB Output is correct
3 Correct 129 ms 114872 KB Output is correct
4 Correct 115 ms 114100 KB Output is correct
5 Correct 179 ms 119448 KB Output is correct

Subtask #3
0.0 / 25.0

# Verdict Execution time Memory Grader output
1 Incorrect 23 ms 95056 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 23 ms 95056 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 23 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 22 ms 94808 KB Output is correct
2 Correct 22 ms 95024 KB Output is correct
3 Correct 22 ms 94812 KB Output is correct
4 Correct 21 ms 94812 KB Output is correct
5 Correct 22 ms 95032 KB Output is correct
6 Correct 22 ms 94812 KB Output is correct
7 Correct 21 ms 95116 KB Output is correct
8 Correct 21 ms 95040 KB Output is correct
9 Correct 21 ms 94808 KB Output is correct
10 Correct 20 ms 94812 KB Output is correct
11 Correct 161 ms 118216 KB Output is correct
12 Correct 169 ms 120512 KB Output is correct
13 Correct 129 ms 114872 KB Output is correct
14 Correct 115 ms 114100 KB Output is correct
15 Correct 179 ms 119448 KB Output is correct
16 Incorrect 23 ms 95056 KB Output isn't correct
17 Halted 0 ms 0 KB -