oj.uz

Submission #817090

# Submission time Handle Problem Language Result Execution time Memory
817090 2023-08-09T09:23:25 Z t6twotwo Parking (CEOI22_parking) C++17
18 / 100
 89 ms 17096 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 43 ms 5264 KB Output is correct
2 Correct 43 ms 6924 KB Output is correct
3 Correct 35 ms 5596 KB Output is correct
4 Correct 31 ms 5332 KB Output is correct
5 Correct 43 ms 6948 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 212 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Partially correct 1 ms 384 KB Output is partially correct
5 Correct 0 ms 340 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Partially correct 1 ms 340 KB Output is partially correct
8 Correct 0 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 212 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Partially correct 1 ms 384 KB Output is partially correct
5 Correct 0 ms 340 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Partially correct 1 ms 340 KB Output is partially correct
8 Correct 0 ms 340 KB Output is correct
9 Partially correct 1 ms 340 KB Output is partially correct
10 Partially correct 89 ms 17096 KB Output is partially correct
11 Correct 27 ms 3352 KB Output is correct
12 Correct 38 ms 5708 KB Output is correct
13 Partially correct 71 ms 9904 KB Output is partially correct
14 Correct 44 ms 10060 KB Output is correct
15 Correct 43 ms 9740 KB Output is correct
16 Partially correct 88 ms 15412 KB Output is partially correct
17 Correct 40 ms 7692 KB Output is correct
18 Partially correct 79 ms 12684 KB Output is partially correct

Subtask #5
0.0 / 25.0

# Verdict Execution time Memory Grader output
1 Runtime error 3 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 -