oj.uz

Submission #817094

# Submission time Handle Problem Language Result Execution time Memory
817094 2023-08-09T09:26:40 Z t6twotwo Parking (CEOI22_parking) C++17
18 / 100
 63 ms 14080 KB 
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define FFOR(i,a,b,c) for(int i=(a);(c)>0?i<=(b):i>=(b);i+=(c))
#define FOOR(i,a,b) FFOR(i,a,(b)-1,1)
#define ROOF(i,a,b) FFOR(i,(b)-1,a,-1)
#define FOR(i,n) FOOR(i,0,n)
#define ROF(i,n) ROOF(i,0,n)
#define FORR(x,v) for(auto &x:v)
#define vc vector
#define sz(v) (int)((v).size())
#define bg begin()
#define en end()
#define em empty()
#define lb lower_bound
#define ub upper_bound
#define pb push_back
#define ppb pop_back()
#define eb emplace_back
#define bk back()
#define fr front()
#define pp pop()
#define all(v) (v).begin(),(v).end()
#define lla(v) (v).rbegin(),(v).rend()
#define f first
#define s second
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N,M;
    cin>>N>>M;
    vc<int> bot(M),top(M),x(N,-1),y(N),free;
    FOR(i,M){
        cin>>bot[i]>>top[i];
        bot[i]--,top[i]--;
        if(bot[i]!=-1) (x[bot[i]]==-1?x[bot[i]]:y[bot[i]])=i*2;
        if(top[i]!=-1) (x[top[i]]==-1?x[top[i]]:y[top[i]])=i*2+1;
        if(bot[i]==-1&&top[i]==-1) free.pb(i);
    }
    vc<pair<int,int>> ans;
    auto move=[&](int u,int v) {
        ans.eb(u,v);
        int a;
        if(top[u]!=-1){
            a=top[u];
            top[u]=-1;
        }else{
            a=bot[u];
            bot[u]=-1;
        }
        if(bot[v]==-1){
            (x[a]/2==u?x[a]:y[a])=v*2;
            bot[v]=a;
        }else{
            (x[a]/2==u?x[a]:y[a])=v*2+1;
            top[v]=a;
        }
        if(bot[u]==-1){
            free.pb(u);
        }
    };
    auto park=[&](int i){
        int a=x[i]/2;
        int b=y[i]/2;
        if(top[b]!=-1) swap(a,b);
        move(a,b);
    };
    auto check=[&](){
        if(free.em){
            cout<<-1;
            exit(0);
        }
    };
    if(2*N<=M){
        auto good=[&](int a) {
            return (x[a]%2==1||top[x[a]/2]==-1)&&(y[a]%2==1||top[y[a]/2]==-1);
        };
        vc<bool> parked(N);
        FOR(i,N){
            if(x[i]%2==1&&y[i]%2==1){
                move(x[i]/2,free.bk);
                move(y[i]/2,free.bk);
                free.ppb;
            }
            if(x[i]/2==y[i]/2) parked[i]=1;
        }
        queue<int> q;
        FOR(i,N){
            if(!parked[i]&&good(i)){
                parked[i]=1;
                q.push(i);
            }
        }
        while(!q.em){
            int i=q.fr;q.pp;
            int a=x[i]/2;
            int b=y[i]/2;
            if(top[b]!=-1) swap(a,b);
            move(a,b);
            if(bot[a]!=-1){
                if(!parked[bot[a]]&&good(bot[a])){
                    parked[bot[a]]=1;
                    q.push(bot[a]);
                }
            }
        }
        FOR(i,N){
            if(!parked[i]){
                cout<<-1;
                return 0;
            }
        }
        cout<<sz(ans)<<"\n";
        for(auto[x,y]:ans){
            cout<<x+1<<" "<<y+1<<"\n";
        }
        return 0;
    }
    vc<bool> vis(M);
    vc<vc<int>> S, P;
    vc<vc<vc<int>>> T;
    FOR(i,M){
        if(vis[i]||bot[i]==top[i])continue;
        int j=i,k=bot[i],f=0;
        S.pb({k});
        P.pb({});
        T.pb({});
        while(1){
            P.bk.pb(j);
            T.bk.pb({});
            vis[j]=1;
            k=f?bot[j]:top[j];
            while(k!=bot[i]&&x[k]%2!=y[k]%2){
                T.bk.bk.pb(k);
                j^=(x[k]/2)^(y[k]/2);
                vis[j]=1;
                k=f?bot[j]:top[j];
                P.bk.pb(j);
            }
            if (k==bot[i])break;
            S.bk.pb(k);
            j^=(x[k]/2)^(y[k]/2);
            f^=1;
        }
    }
    FOR(i,sz(S)){
        if (sz(S[i])==1){
            check();
            move(P[i].bk,free.bk);
            ROF(j,sz(T[i][0])) park(T[i][0][j]);
            move(free.bk,P[i][0]);
            continue;
        }
        check(); int t=free.bk; free.ppb;
        move(x[S[i][1]]/2,t);
        move(y[S[i][1]]/2,t);
        ROF(j,sz(T[i][0])) park(T[i][0][j]);
        FOR(j,sz(T[i][1])) park(T[i][1][j]);
        FFOR(j,3,sz(S[i])-1,2){
            check(); int t=free.bk;free.ppb;
            move(x[S[i][j]]/2,t);
            move(y[S[i][j]]/2,t);
            ROF(k,sz(T[i][j-1])) park(T[i][j-1][k]);
            FOR(k,sz(T[i][j])) park(T[i][j][k]);
            park(S[i][j-1]);
        }
        park(S[i][0]);
        if(sz(S[i])%2){
            FOR(j,sz(T[i].bk)) park(T[i].bk[j]);
            park(S[i].bk);
        }
    }
    cout<<sz(ans)<<"\n";
    // for(auto[x,y]:ans){
        // cout<<x+1<<" "<<y+1<<"\n";
    // }
    return 6/22;
}

Subtask #1
0.0 / 10.0

# Verdict Execution time Memory Grader output
1 Incorrect 0 ms 212 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 5192 KB Output is correct
2 Correct 42 ms 5512 KB Output is correct
3 Correct 30 ms 4360 KB Output is correct
4 Correct 29 ms 4200 KB Output is correct
5 Correct 41 ms 5448 KB Output is correct

Subtask #3
5.0 / 25.0

# Verdict Execution time Memory Grader output
1 Partially correct 1 ms 340 KB Output is partially correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Partially correct 1 ms 340 KB Output is partially correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Partially correct 1 ms 340 KB Output is partially correct
8 Correct 1 ms 340 KB Output is correct
9 Partially correct 1 ms 340 KB Output is partially correct

Subtask #4
3.0 / 15.0

# Verdict Execution time Memory Grader output
1 Partially correct 1 ms 340 KB Output is partially correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Partially correct 1 ms 340 KB Output is partially correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Partially correct 1 ms 340 KB Output is partially correct
8 Correct 1 ms 340 KB Output is correct
9 Partially correct 1 ms 340 KB Output is partially correct
10 Partially correct 63 ms 14080 KB Output is partially correct
11 Correct 27 ms 3364 KB Output is correct
12 Correct 46 ms 5684 KB Output is correct
13 Partially correct 47 ms 7860 KB Output is partially correct
14 Correct 44 ms 10132 KB Output is correct
15 Correct 43 ms 9800 KB Output is correct
16 Partially correct 62 ms 12312 KB Output is partially correct
17 Correct 43 ms 7596 KB Output is correct
18 Partially correct 63 ms 10216 KB Output is partially correct

Subtask #5
0.0 / 25.0

# Verdict Execution time Memory Grader output
1 Runtime error 1 ms 980 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #6
0.0 / 15.0

# Verdict Execution time Memory Grader output
1 Incorrect 0 ms 212 KB Output isn't correct
2 Halted 0 ms 0 KB -