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Submission #817255

# Submission time Handle Problem Language Result Execution time Memory
817255 2023-08-09T11:04:43 Z t6twotwo Parking (CEOI22_parking) C++17
50 / 100
 2000 ms 9092 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(a==b)return;
        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);
    FOR(i,N) {
        // if((x[i]%2==0&&y[i]%2==0&&top[x[i]/2]==-1&&top[y[i]/2]==-1)) while(1){};
    }
    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){
            // assert(sz(S)!=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){
        assert(x!=y);
        cout<<x+1<<" "<<y+1<<"\n";
    }
    return 6/22;
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 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 2074 ms 4076 KB Time limit exceeded
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 0 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 0 ms 212 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 0 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 0 ms 212 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 89 ms 8928 KB Output is correct
11 Correct 33 ms 3660 KB Output is correct
12 Correct 35 ms 3752 KB Output is correct
13 Correct 70 ms 8004 KB Output is correct
14 Correct 35 ms 3852 KB Output is correct
15 Correct 35 ms 3676 KB Output is correct
16 Correct 86 ms 9092 KB Output is correct
17 Correct 38 ms 3708 KB Output is correct
18 Correct 90 ms 8512 KB Output is correct

Subtask #5
0.0 / 25.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2062 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 1 ms 212 KB Output is correct
2 Correct 1 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 2074 ms 4076 KB Time limit exceeded
12 Halted 0 ms 0 KB -