oj.uz

Submission #701330

# Submission time Handle Problem Language Result Execution time Memory
701330 2023-02-20T23:52:29 Z Lobo Parking (CEOI22_parking) C++17
20 / 100
 146 ms 42388 KB 
#include<bits/stdc++.h>
using namespace std;
const long long inf = (long long) 1e18 + 10;
const int inf1 = (int) 1e9 + 10;
#define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
const int maxn = 2e5+10;

int n, m, b[maxn], t[maxn], done[maxn], mark[maxn], rec[maxn];
vector<int> gin[maxn], got[maxn], need[maxn], has[maxn], pos[maxn], ept;
vector<pair<int,int>> ans;

void add(vector<int> &vec, int x) {
    for(auto v : vec) if(v == x) return;
    vec.pb(x);
}

void remove(vector<int> &vec, int x) {
    vector<int> newv;
    for(auto v : vec) if(v != x) newv.pb(v);
    vec = newv;
}

void dfs(int u) {
    mark[u] = 1;
    rec[u] = 1;

    if(got[u].size() == 2) {
        add(need[u],u);
    }

    for(auto v : gin[u]) {
        if(rec[v]) {

        }
        else {
            if(!mark[v]) dfs(v);
            for(auto x : need[v]) add(need[u],x);
        }
    }
    rec[u] = 0;
}

void solve() {
    cin >> n >> m;

    for(int i = 1; i <= m; i++) {
        cin >> b[i] >> t[i];
        if(b[i] != 0) pos[b[i]].pb(i);
        if(t[i] != 0) pos[t[i]].pb(i+m);
        if(b[i] == 0) {
            ept.pb(i);
        }
        else if(b[i] == t[i]) {
            done[b[i]] = 1;
        }
        else if(t[i] != 0) {
            got[t[i]].pb(b[i]);
            gin[b[i]].pb(t[i]);
        }
    }

    for(int i = 1; i <= n; i++) {
        if(!mark[i]) dfs(i);
    }

    priority_queue<pair<int,int>, vector<pair<int,int>>, greater<pair<int,int>>> pq;
    for(int i = 1; i <= n; i++) {
        if(got[i].size() == 0) {
            pq.push(mp(need[i].size(),i));
        }

        for(auto x : need[i]) {
            has[x].pb(i);
        }
    }
    queue<int> q;
    for(int i = 1; i <= n; i++) {
        if(!done[i] && gin[i].size() == 0 && got[i].size() != 2) {
            q.push(i);
        }
    }

    while(pq.size()) {
        int i = pq.top().sc; pq.pop();
        if(done[i]) continue;
        if(ept.size() < need[i].size()) {
            cout << -1 << endl;
            return;
        }
        for(auto v : need[i]) {
            sort(all(pos[v]));
            int p1 = pos[v][0]-m;
            int p2 = pos[v][1]-m;
            int e = ept.back(); ept.pop_back();
            ans.pb(mp(p1,e));
            t[p1] = 0;
            b[e] = v;
            pos[v][0] = e;
            ans.pb(mp(p2,e));
            t[p2] = 0;
            t[e] = v;
            pos[v][1] = e+m;

            done[v] = 1;
            for(auto x : got[v]) {
                remove(gin[x],v);
                if(gin[x].size() == 0) {
                    q.push(x);
                }
            }

            for(auto x : has[v]) {
                remove(need[x],v);
                if(got[x].size() == 0) pq.push(mp(need[x].size(),x));
            }
        }

        while(q.size()) {
            int v = q.front(); q.pop();
            if(got[v].size() == 1) {
                sort(all(pos[v]));
                int p1 = pos[v][0];
                int p2 = pos[v][1]-m;

                ans.pb(mp(p2,p1));
                t[p2] = 0;
                t[p1] = v;
                pos[v][1] = p1+m;

                done[v] = 1;
                for(auto x : got[v]) {
                    remove(gin[x],v);
                    if(gin[x].size() == 0) {
                        q.push(x);
                    }
                }
            }
            else {
                sort(all(pos[v]));
                int p1 = pos[v][0];
                int p2 = pos[v][1];

                ans.pb(mp(p2,p1));
                b[p2] = 0;
                ept.pb(p2);
                t[p1] = v;
                pos[v][1] = p1+m;

                done[v] = 1;
                for(auto x : got[v]) {
                    remove(gin[x],v);
                    if(gin[x].size() == 0) {
                        q.push(x);
                    }
                }
            }
        }
    }

    //solve cycles
    for(int i = 1; i <= n; i++) {
        if(!done[i]) {
            if(ept.size() < 1) {
                cout << -1 << endl;
                return;
            }
            queue<int> q;
            sort(all(pos[i]));
            int p1 = pos[i][0];
            int p2 = pos[i][1]-m;
            int e = ept.back(); ept.pop_back();
            ans.pb(mp(p2,e));
            t[p2] = 0;
            b[e] = i;
            pos[i][1] = e;
            remove(got[i],b[p2]);
            remove(gin[b[p2]],i);
            if(gin[b[p2]].size() == 0) {
                q.push(b[p2]);
            }

            while(q.size()) {
                int v = q.front(); q.pop();
                if(got[v].size() == 1) {
                    sort(all(pos[v]));
                    int p1 = pos[v][0];
                    int p2 = pos[v][1]-m;

                    ans.pb(mp(p2,p1));
                    t[p2] = 0;
                    t[p1] = v;
                    pos[v][1] = p1+m;

                    done[v] = 1;
                    for(auto x : got[v]) {
                        remove(gin[x],v);
                        if(gin[x].size() == 0) {
                            q.push(x);
                        }
                    }
                }
                else {
                    sort(all(pos[v]));
                    int p1 = pos[v][0];
                    int p2 = pos[v][1];

                    ans.pb(mp(p2,p1));
                    b[p2] = 0;
                    ept.pb(p2);
                    t[p1] = v;
                    pos[v][1] = p1+m;

                    done[v] = 1;
                    for(auto x : got[v]) {
                        remove(gin[x],v);
                        if(gin[x].size() == 0) {
                            q.push(x);
                        }
                    }
                }
            }
        }
    }

    cout << ans.size() << endl;
    for(auto x : ans) {
        cout << x.fr << " " << x.sc << endl;
    }
}

int32_t main() {
    ios::sync_with_stdio(false); cin.tie(0);

    // freopen("in.in", "r", stdin);
    // freopen("out.out", "w", stdout);
    int tt = 1;
    // cin >> tt;
    while(tt--) {
        solve();
    }

}

Compilation message

Main.cpp: In function 'void solve()':
Main.cpp:176:17: warning: unused variable 'p1' [-Wunused-variable]
  176 |             int p1 = pos[i][0];
      |                 ^~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 23764 KB Output is correct
2 Correct 12 ms 23816 KB Output is correct
3 Correct 14 ms 23764 KB Output is correct
4 Correct 14 ms 23824 KB Output is correct
5 Correct 13 ms 23892 KB Output is correct
6 Correct 13 ms 23764 KB Output is correct
7 Correct 13 ms 23764 KB Output is correct
8 Correct 13 ms 23764 KB Output is correct
9 Correct 14 ms 23812 KB Output is correct
10 Correct 13 ms 23764 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 109 ms 39248 KB Output is correct
2 Correct 146 ms 42388 KB Output is correct
3 Correct 81 ms 36292 KB Output is correct
4 Correct 72 ms 35536 KB Output is correct
5 Correct 144 ms 42220 KB Output is correct

Subtask #3
0.0 / 25.0

# Verdict Execution time Memory Grader output
1 Incorrect 13 ms 23944 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 13 ms 23944 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #5
0.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 24020 KB Output is correct
2 Correct 13 ms 23964 KB Output is correct
3 Correct 13 ms 23944 KB Output is correct
4 Incorrect 13 ms 23944 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #6
0.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 23764 KB Output is correct
2 Correct 12 ms 23816 KB Output is correct
3 Correct 14 ms 23764 KB Output is correct
4 Correct 14 ms 23824 KB Output is correct
5 Correct 13 ms 23892 KB Output is correct
6 Correct 13 ms 23764 KB Output is correct
7 Correct 13 ms 23764 KB Output is correct
8 Correct 13 ms 23764 KB Output is correct
9 Correct 14 ms 23812 KB Output is correct
10 Correct 13 ms 23764 KB Output is correct
11 Correct 109 ms 39248 KB Output is correct
12 Correct 146 ms 42388 KB Output is correct
13 Correct 81 ms 36292 KB Output is correct
14 Correct 72 ms 35536 KB Output is correct
15 Correct 144 ms 42220 KB Output is correct
16 Incorrect 13 ms 23944 KB Output isn't correct
17 Halted 0 ms 0 KB -