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Submission #677447

# Submission time Handle Problem Language Result Execution time Memory
677447 2023-01-03T11:31:48 Z stanislavpolyn Parking (CEOI22_parking) C++17
20 / 100
 125 ms 16484 KB 
#include <bits/stdc++.h>

#define fr(i, a, b) for (int i = (a); i <= (b); ++i)
#define rf(i, a, b) for (int i = (a); i >= (b); --i)
#define fe(x, y) for (auto& x : y)

#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define mt make_tuple

#define all(x) (x).begin(), (x).end()
#define pw(x) (1LL << (x))
#define sz(x) (int)(x).size()

using namespace std;

mt19937_64 rng(228);

#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template <typename T>
using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define fbo find_by_order
#define ook order_of_key

template <typename T>
bool umn(T& a, T b) {
    return a > b ? (a = b, 1) : 0;
}
template <typename T>
bool umx(T& a, T b) {
    return a < b ? (a = b, 1) : 0;
}

using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
template <typename T>
using ve = vector<T>;

const int N = 2e5 + 5;

int n, m;
int a[N][2];
ve<pii> opers;
ve<pii> pos[N];
set<int> emp;

void doOper(int i, int j) {
//    cout << "MAKE OPER " << i << " " << j << "\n" << flush;

    assert(i != j);
    assert(a[i][0]);

    int x = a[i][1] ? a[i][1] : a[i][0];

//    cout << "x: " << x << "\n";
    int from = a[i][1] ? 1 : 0;
    assert(!a[j][1]);
    assert(a[j][0] == 0 || a[j][0] == x);
//    cout << i << " " << from << "\n";

    int idx = -1;
    fr (cur, 0, 1) {
        if (pos[x][cur].fi == i && pos[x][cur].se == from) {
            idx = cur;
            break;
        }
    }
    assert(idx != -1);

    if (from == 0) {
        emp.insert(i);
    }

    if (a[j][0] == 0) {
        a[i][from] = 0;
        a[j][0] = x;
        pos[x][idx] = {j, 0};
        emp.erase(j);
    } else {
        assert(a[j][0]);
        a[i][from] = 0;
        a[j][1] = x;
        pos[x][idx] = {j, 1};
    }
    opers.pb({i, j});
}

int main() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#else
    ios::sync_with_stdio(0);
    cin.tie(0);
#endif

    cin >> n >> m;

    fr (i, 1, m) {
        cin >> a[i][0] >> a[i][1];

        if (a[i][0]) {
            pos[a[i][0]].pb({i, 0});
        }
        if (a[i][1]) {
            pos[a[i][1]].pb({i, 1});
        }
    }

    fr (i, 1, m) {
        if (!a[i][0]) {
            emp.insert(i);
        }
    }

    while (1) {
        bool found = 0;
        int cnt = 0;
        fr (i, 1, n) {
            if (pos[i][0].fi == pos[i][1].fi) {
                cnt++;
                continue;
            }

            int i1 = pos[i][0].fi;
            int j1 = pos[i][0].se;
            int i2 = pos[i][1].fi;
            int j2 = pos[i][1].se;

//            if (i == 2) {
//                cout << "YEP\n";
//                cout << i1 << " " << j1 << " " << i2 << " " << j2 << "\n";
//            }

            if (j1 == 1 || !a[i1][1]) {
                if (j2 == 0 && !a[i2][1]) {

                    doOper(i1, i2);
                    found = 1;
                    continue;
                }
            }
            if (j2 == 1 || !a[i2][1]) {
                if (j1 == 0 && !a[i1][1]) {
                    doOper(i2, i1);
                    found = 1;
                }
            }

        }

        if (cnt == n) {
            cout << sz(opers) << "\n";
            fe (x, opers) {
                cout << x.fi << " " << x.se << "\n";
            }
            return 0;
        }

        if (found) {
            continue;
        }

        fr (i, 1, n) {
            if (pos[i][0].fi == pos[i][1].fi) {
                continue;
            }

            int i1 = pos[i][0].fi;
            int j1 = pos[i][0].se;
            int i2 = pos[i][1].fi;
            int j2 = pos[i][1].se;

            if (j1 == 1 && j2 == 1) {
                if (sz(emp)) {
                    int to = *emp.begin();
                    doOper(i1, to);
                    doOper(i2, to);
                    found = 1;
                }
            }
        }

        if (found) {
            continue;
        }

//        cout << "YEP HERE\n";

        fr (i, 1, n) {
            if (pos[i][0].fi == pos[i][1].fi) {
               continue;
            }

            int i1 = pos[i][0].fi;
            int j1 = pos[i][0].se;
            int i2 = pos[i][1].fi;
            int j2 = pos[i][1].se;

            if (j1 != j2) {
                if (j1 == 0) {
                    if (!sz(emp)) {
                        cout << "-1\n";
                        return 0;
                    }
                    int to = *emp.begin();
                    doOper(i1, to);
                    found = 1;
                    break;
                }
                if (j2 == 0) {
                    if (!sz(emp)) {
                        cout << "-1\n";
                        return 0;
                    }
                    int to = *emp.begin();
                    doOper(i2, to);
                    found = 1;
                    break;
                }
            }
        }

        if (!found) {
            cout << "-1\n";
            return 0;
        }
    }

    return 0;
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4948 KB Output is correct
2 Correct 2 ms 4948 KB Output is correct
3 Correct 2 ms 4948 KB Output is correct
4 Correct 2 ms 4948 KB Output is correct
5 Correct 3 ms 4948 KB Output is correct
6 Correct 2 ms 4948 KB Output is correct
7 Correct 2 ms 4948 KB Output is correct
8 Correct 2 ms 4948 KB Output is correct
9 Correct 3 ms 4948 KB Output is correct
10 Correct 2 ms 4948 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 101 ms 16152 KB Output is correct
2 Correct 117 ms 16208 KB Output is correct
3 Correct 88 ms 15884 KB Output is correct
4 Correct 91 ms 15960 KB Output is correct
5 Correct 125 ms 16484 KB Output is correct

Subtask #3
0.0 / 25.0

# Verdict Execution time Memory Grader output
1 Incorrect 2 ms 4948 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0.0 / 15.0

# Verdict Execution time Memory Grader output
1 Incorrect 2 ms 4948 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #5
0.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5076 KB Output is correct
2 Correct 3 ms 5028 KB Output is correct
3 Correct 3 ms 5028 KB Output is correct
4 Correct 3 ms 5076 KB Output is correct
5 Correct 3 ms 5076 KB Output is correct
6 Correct 3 ms 5076 KB Output is correct
7 Correct 3 ms 5032 KB Output is correct
8 Incorrect 4 ms 5028 KB Output isn't correct
9 Halted 0 ms 0 KB -

Subtask #6
0.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4948 KB Output is correct
2 Correct 2 ms 4948 KB Output is correct
3 Correct 2 ms 4948 KB Output is correct
4 Correct 2 ms 4948 KB Output is correct
5 Correct 3 ms 4948 KB Output is correct
6 Correct 2 ms 4948 KB Output is correct
7 Correct 2 ms 4948 KB Output is correct
8 Correct 2 ms 4948 KB Output is correct
9 Correct 3 ms 4948 KB Output is correct
10 Correct 2 ms 4948 KB Output is correct
11 Correct 101 ms 16152 KB Output is correct
12 Correct 117 ms 16208 KB Output is correct
13 Correct 88 ms 15884 KB Output is correct
14 Correct 91 ms 15960 KB Output is correct
15 Correct 125 ms 16484 KB Output is correct
16 Incorrect 2 ms 4948 KB Output isn't correct
17 Halted 0 ms 0 KB -