oj.uz

Submission #817225

# Submission time Handle Problem Language Result Execution time Memory
817225 2023-08-09T10:48:12 Z t6twotwo Parking (CEOI22_parking) C++17
50 / 100
 84 ms 8624 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[a]!=-1&&top[b]!=-1) return;
        if(x[i]%2==1&&y[i]%2==1) return;
        if(x[i]%2==0&&top[a]!=-1) return;
        if(y[i]%2==0&&top[b]!=-1) return;
        if(top[b]!=-1) swap(a,b);
        move(a,b);
    };
    auto get=[&](){
        if(free.em){
            cout<<-1;
            exit(0);
        }
        int t=free.bk;
        free.ppb;
        return t;
    };
    FOR(i,M){
        if(top[i]==-1&&bot[i]!=-1){
            int j=i,k=bot[i];
            while(x[k]%2!=y[k]%2){
                j^=(x[k]/2)^(y[k]/2);
                park(k);
                k=bot[j];
            }
        }
    }
    FOR(i,N) park(i);
    vc<bool> vis(M);
    FOR(i,M){
        if(vis[i]||bot[i]==top[i])continue;
        vis[i]=1;
        int k=bot[i],f=0,j=top[i]==-1?(i^(x[k]/2)^(y[k]/2)):i;
        if(top[i]==-1){
            assert(!(x[k]%2==0&&y[k]%2==0&&top[x[k]/2]==-1&&top[y[k]/2]==-1));
        }
        vc<int> S{k};
        vc<vc<int>> T;
        while(1){
            T.pb({});
            vis[j]=1;
            k=f?bot[j]:top[j];
            while(k!=-1&&k!=bot[i]&&x[k]%2!=y[k]%2){
                T.bk.pb(k);
                j^=(x[k]/2)^(y[k]/2);
                vis[j]=1;
                k=f?bot[j]:top[j];
            }
            if (k==bot[i]||k==-1)break;
            S.pb(k);
            j^=(x[k]/2)^(y[k]/2);
            f^=1;
        }
        if(top[i]==-1){
            FFOR(j,1,sz(S)-2,2){
                int t=get();
                move(x[S[j]]/2,t);
                move(y[S[j]]/2,t);
                ROF(k,sz(T[j-1])) park(T[j-1][k]);
                FOR(k,sz(T[j])) park(T[j][k]);
                park(S[j-1]);
            }
            park(S.bk);
        }else{
            if (sz(S)==1){
                int t=get();
                int a=x[S[0]];
                int b=y[S[0]];
                if (a%2==0) swap(a,b);
                move(a/2,t);
                ROF(j,sz(T[0])) park(T[0][j]);
                move(b/2,t);
                continue;
            }
            int t=get();
            move(x[S[1]]/2,t);
            move(y[S[1]]/2,t);
            ROF(j,sz(T[0])) park(T[0][j]);
            FOR(j,sz(T[1])) park(T[1][j]);
            FFOR(j,3,sz(S)-1,2){
                int t=get();
                move(x[S[j]]/2,t);
                move(y[S[j]]/2,t);
                ROF(k,sz(T[j-1])) park(T[j-1][k]);
                FOR(k,sz(T[j])) park(T[j][k]);
                park(S[j-1]);
            }
            park(S[0]);
            if(sz(S)%2){
                ROF(j,sz(T.bk)) park(T.bk[j]);
                park(S.bk);
            }
        }
    }
    cout<<sz(ans)<<"\n";
    for(auto[x,y]:ans){
        cout<<x+1<<" "<<y+1<<"\n";
    }
    return 6/22;
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 0 ms 212 KB Output is correct

Subtask #2
0.0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 31 ms 7084 KB Execution killed with signal 6
2 Halted 0 ms 0 KB -

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 1 ms 340 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 79 ms 8528 KB Output is correct
11 Correct 28 ms 3376 KB Output is correct
12 Correct 31 ms 3368 KB Output is correct
13 Correct 69 ms 7600 KB Output is correct
14 Correct 33 ms 3436 KB Output is correct
15 Correct 31 ms 3348 KB Output is correct
16 Correct 84 ms 8624 KB Output is correct
17 Correct 29 ms 3320 KB Output is correct
18 Correct 78 ms 8124 KB Output is correct

Subtask #5
0.0 / 25.0

# Verdict Execution time Memory Grader output
1 Runtime error 1 ms 468 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 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Runtime error 31 ms 7084 KB Execution killed with signal 6
12 Halted 0 ms 0 KB -