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Submission #817227

# Submission time Handle Problem Language Result Execution time Memory
817227 2023-08-09T10:48:35 Z t6twotwo Parking (CEOI22_parking) C++17
50 / 100
 2000 ms 8644 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){
            if((x[k]%2==0&&y[k]%2==0&&top[x[k]/2]==-1&&top[y[k]/2]==-1)) while(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 Execution timed out 2045 ms 4016 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 0 ms 340 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 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 0 ms 340 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 0 ms 340 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 77 ms 8600 KB Output is correct
11 Correct 27 ms 3364 KB Output is correct
12 Correct 30 ms 3364 KB Output is correct
13 Correct 65 ms 7620 KB Output is correct
14 Correct 37 ms 3456 KB Output is correct
15 Correct 30 ms 3348 KB Output is correct
16 Correct 85 ms 8644 KB Output is correct
17 Correct 30 ms 3328 KB Output is correct
18 Correct 72 ms 8152 KB Output is correct

Subtask #5
0.0 / 25.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2054 ms 340 KB Time limit exceeded
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 Execution timed out 2045 ms 4016 KB Time limit exceeded
12 Halted 0 ms 0 KB -