oj.uz

Submission #677476

# Submission time Handle Problem Language Result Execution time Memory
677476 2023-01-03T12:15:03 Z stanislavpolyn Parking (CEOI22_parking) C++17
20 / 100
 122 ms 16444 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 assertTL(bool f) {
    if (!f) {
        while (1);
    }
}

bool TL() {
    return (double)clock() / CLOCKS_PER_SEC > 1.9;
}

void doOper(int i, int j) {
    assertTL(i != j);
    assertTL(a[i][0]);

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

    int from = a[i][1] ? 1 : 0;
    assertTL(!a[j][1]);
    assertTL(a[j][0] == 0 || a[j][0] == x);

    int idx = -1;
    fr (cur, 0, 1) {
        if (pos[x][cur].fi == i && pos[x][cur].se == from) {
            idx = cur;
            break;
        }
    }
    assertTL(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 {
        assertTL(a[j][0]);
        a[i][from] = 0;
        a[j][1] = x;
        pos[x][idx] = {j, 1};
    }
    opers.pb({i, j});

//    fr (i, 1, m) {
//        if (!a[i][0]) assertTL(emp.count(i));
//        else assertTL(!emp.count(i));
//
//        if (a[i][0]) assertTL(pos[a[i][0]][0] == mp(i, 0) || pos[a[i][0]][1] == mp(i, 0));
//        if (a[i][1]) assertTL(pos[a[i][1]][0] == mp(i, 1) || pos[a[i][1]][1] == mp(i, 1));
//        if (a[i][1]) {
//            assertTL(a[i][0]);
//        }
//    }
}

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;

    assert(n <= int(2e5));
    assert(n >= 1);
    assert(m <= int(2e5));

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

        assert(a[i][0] >= 0 && a[i][0] <= n);
        assert(a[i][1] >= 0 && a[i][1] <= n);

        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, n) {
        assert(sz(pos[i]) == 2);
    }

    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 (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) {
            fr (i, 1, m) {
                if (a[i][0]) {
                    assert(a[i][0] == a[i][1]);
                }
            }

//            assert(0);

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

        if (found) {
            continue;
        }

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

        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;
            }

            if (sz(emp)) {
                assert(pos[i][0].se != pos[i][1].se);
            }
        }

        bool ok = 0;
        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) {
                ok = 1;

                if (j1 == 0) {
                    if (sz(emp)) {
                        int to = *emp.begin();
                        doOper(i1, to);
                        doOper(i2, i1);
                        found = 1;
                        break;
                    }
                }
                if (j2 == 0) {
                    if (sz(emp)) {
                        int to = *emp.begin();
                        doOper(i2, to);
                        doOper(i1, i2);
                        found = 1;
                        break;
                    }
                }
            }
        }
        assert(ok);

        if (!found) {
            bool have = 0;
            fr (i, 1, m) {
                fr (j, 1, m) {
                    if (i == j) continue;
                    if (!a[i][0]) continue;
                    if (a[j][1]) continue;

                    int x = a[i][1] ? a[i][1] : a[i][0];
                    if (!a[j][0] || a[j][0] == x) {
                        have = 1;
                    }
                }
            }

            assert(!have);

            cout << "-1\n";
            return 0;
        }
    }

    return 0;
}

Subtask #1
10.0 / 10.0

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

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 122 ms 16104 KB Output is correct
2 Correct 119 ms 16192 KB Output is correct
3 Correct 96 ms 15932 KB Output is correct
4 Correct 102 ms 16072 KB Output is correct
5 Correct 120 ms 16444 KB Output is correct

Subtask #3
0.0 / 25.0

# Verdict Execution time Memory Grader output
1 Incorrect 3 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 3 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 4948 KB Output is correct
3 Correct 3 ms 5076 KB Output is correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 3 ms 4948 KB Output is correct
6 Correct 3 ms 5076 KB Output is correct
7 Correct 3 ms 4948 KB Output is correct
8 Incorrect 2 ms 4948 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 3 ms 4948 KB Output is correct
2 Correct 4 ms 4948 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 3 ms 4948 KB Output is correct
5 Correct 2 ms 4948 KB Output is correct
6 Correct 2 ms 4948 KB Output is correct
7 Correct 3 ms 4948 KB Output is correct
8 Correct 2 ms 4948 KB Output is correct
9 Correct 2 ms 4948 KB Output is correct
10 Correct 3 ms 4948 KB Output is correct
11 Correct 122 ms 16104 KB Output is correct
12 Correct 119 ms 16192 KB Output is correct
13 Correct 96 ms 15932 KB Output is correct
14 Correct 102 ms 16072 KB Output is correct
15 Correct 120 ms 16444 KB Output is correct
16 Incorrect 3 ms 4948 KB Output isn't correct
17 Halted 0 ms 0 KB -