Submission #1189914

#	Time	Username	Problem	Language	Result	Execution time	Memory
1189914		Gray	Parking (CEOI22_parking)	C++20	0 / 100	2096 ms	589824 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define ll int
#define ull unsigned long long
#define ld long double
#define ff first
#define ss second
#define ln "\n"
#define mp make_pair
#define pb push_back
#define INF (ll)1e18
ll MOD = (ll)(1e9+7);
vector<pair<ll, ll>> ops;
vector<vector<ll>> s;

vector<pair<ll, ll>> ans;
ll n, m, poss=0;
void search(ll opcnt){
    if (!ans.empty() and ops.size()>=ans.size()) return;
    bool pos=1;
    for (ll i=0; i<m; i++){
        if (s[i].size()==1 or (s[i].size()==2 and s[i][0]!=s[i][1])) pos=0;
    }
    if (pos){
        poss=1;
        if (ans.size()==0 or ans.size()>ops.size()){
            ans=ops;
        }
    }else{
        for (ll i=0; i<m; i++){
            // if (s[i].empty() or (s[i].size()==2 and s[i][0]==s[i][1])) continue;
            for (ll j=0; j<m; j++){
                if (i!=j and !s[i].empty() and !(s[i].size()==1 and s[j].empty() and !(s[i].size()==2 and s[i][0]==s[i][1]))){
                    if((s[j].empty() or s[j].back()==s[i].back()) and s[j].size()<2){
                        s[j].push_back(s[i].back()); s[i].pop_back();
                        ops.push_back({i+1, j+1});
                        search(opcnt+1);
                        ops.pop_back();
                        s[i].push_back(s[j].back()); s[j].pop_back();
                    }
                }
            }
        }
    }
}

void solve(){
    cin >> n >> m; s.resize(m);
    for (ll i=0; i<m; i++){
        ll b, t; cin >> b >> t;
        if (b!=0) s[i].push_back(b);
        if (t!=0) s[i].push_back(t);
    }
    search(0);
    if (!poss){
        cout << -1 << ln; return;
    }
    cout << ans.size() << ln;
    for (auto ch:ans) cout << ch.ff << " " << ch.ss << ln;
}

int main(){
    ios_base::sync_with_stdio(false); cin.tie(nullptr);
    #ifdef LOCAL
    auto start = chrono::high_resolution_clock::now();
    #endif
    ll testc=1;
    // cin >> testc;
    for (ll __c=1; __c<=testc; __c++) solve();
    #ifdef LOCAL
    auto duration = chrono::duration_cast<chrono::microseconds>(chrono::high_resolution_clock::now() - start);
    cout << setprecision(0) << fixed << "time: " << (double)duration.count()/1000.0 << " milliseconds" << endl;
    #endif
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 25
• Subtask 4: 0 / 15
• Subtask 5: 0 / 25
• Subtask 6: 0 / 15