oj.uz

답안 #862202

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
862202 2023-10-17T17:08:08 Z vgtcross Parking (CEOI22_parking) C++17
20 / 100
 172 ms 19776 KB 
#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using pii = pair<ll, ll>;

int enc(array<int, 8> &a) {
    int b = 0;
    for (int i : a) b = 5*b + i;
    return b;
}

array<int, 8> dec(int b) {
    array<int, 8> a;
    for (int i = 7; i >= 0; --i) {
        a[i] = b % 5;
        b /= 5;
    }
    return a;
}

void solve() {
    int n, m;
    cin >> n >> m;
    
    if (m <= 4) {
        array<int, 8> a;
        for (int i = 0; i < 2*m; ++i) cin >> a[i];

        vector<bool> vis(4e5, 0);
        vector<int> p(4e5);
        vector<pii> mov(4e5);

        int b = enc(a);
        vis[b] = 1;
        p[b] = -1;
        queue<int> bfs;
        bfs.push(b);
        while (bfs.size()) {
            b = bfs.front();
            bfs.pop();
            a = dec(b);

            bool g = 1;
            for (int i = 0; i < m; ++i) g &= a[2*i] == a[2*i+1];
            if (g) {
                vector<pii> ans;
                while (p[b] != -1) {
                    ans.push_back(mov[b]);
                    b = p[b];
                }
                reverse(ans.begin(), ans.end());
                cout << ans.size() << '\n';
                for (pii q : ans) cout << q.first << ' ' << q.second << '\n';
                return;
            }

            for (int i = 0; i < m; ++i) if (a[2*i] != 0) {
                for (int j = 0; j < m; ++j) if (i != j && a[2*j+1] == 0) {
                    int x = a[2*i+1] != 0;
                    int y = a[2*j] != 0;
                    swap(a[2*i+x], a[2*j+y]);
                    int c = enc(a);
                    if (!vis[c]) {
                        vis[c] = 1;
                        p[c] = b;
                        mov[c] = {i+1, j+1};
                        bfs.push(c);
                    }
                    swap(a[2*i+x], a[2*j+y]);
                }
            }
        }

        cout << "-1\n";
    } else {
        vector<array<int, 2>> g(m+1);
        vector<vector<int>> pos(n+1);
        vector<int> abv(n+1, 0);
        set<int> rem;
        vector<int> f;
        for (int i = 0; i < m; ++i) {
            int a, b;
            cin >> a >> b;
            g[i][0] = a;
            g[i][1] = b;
            if (a) pos[a].push_back(i);
            if (b) pos[b].push_back(i);
            if (a != 0 && a != b) {
                rem.insert(a);
                if (b != 0) rem.insert(b);
            }
            if (b != 0) ++abv[a];
            if (a == 0 && b == 0) f.push_back(i);
        }
        
        vector<pii> ans;
        set<int> nx;
        for (int i = 1; i <= n; ++i) if (rem.count(i) && abv[i] == 0) nx.insert(i);
        while (rem.size()) {
            if (nx.size()) {
                int a = *nx.begin();
                int i = pos[a][0];
                int j = pos[a][1];
                if (g[i][0] == a && g[j][0] == a) {
                    ans.push_back({j, i});
                    swap(g[i][1], g[j][0]);
                    pos[a][1] = i;
                    f.push_back(j);
                } else if (g[i][0] == a && g[j][1] == a) {
                    ans.push_back({j, i});
                    swap(g[i][1], g[j][1]);
                    pos[a][1] = i;
                    if (--abv[g[j][0]] == 0) nx.insert(g[j][0]);
                } else if (g[i][1] == a && g[j][0] == a) {
                    ans.push_back({i, j});
                    swap(g[j][1], g[i][1]);
                    pos[a][0] = i;
                    if (--abv[g[i][0]] == 0) nx.insert(g[i][0]);
                } else {
                    if (f.empty()) {
                        cout << "-1\n";
                        return;
                    }
                    int k = f.back();
                    f.pop_back();
                    ans.push_back({i, k});
                    ans.push_back({j, k});
                    swap(g[k][0], g[i][1]);
                    swap(g[k][1], g[j][1]);
                    pos[a][0] = k;
                    pos[a][1] = k;
                    if (--abv[g[i][0]] == 0) nx.insert(g[i][0]);
                    if (--abv[g[j][0]] == 0) nx.insert(g[j][0]);
                }
                nx.erase(a);
                rem.erase(a);
            } else {
                int a = *rem.begin();
                int i = pos[a][0];
                int j = pos[a][1];
                if (f.empty()) {
                    cout << "-1\n";
                    return;
                }
                int k = f.back();
                f.pop_back();
                if (g[i][1] == a) {
                    ans.push_back({i, k});
                    swap(g[k][0], g[i][1]);
                    pos[a][0] = k;
                    if (--abv[g[i][0]] == 0) nx.insert(g[i][0]);
                } else {
                    ans.push_back({j, k});
                    swap(g[k][0], g[j][1]);
                    pos[a][1] = k;
                    if (--abv[g[j][0]] == 0) nx.insert(g[j][0]);
                }
            }
        }
        
        cout << ans.size() << '\n';
        for (pii p : ans) cout << p.first+1 << ' ' << p.second+1 << '\n';
    }
}

int main() {
    cin.tie(0) -> sync_with_stdio(0);
    
    solve();
}

Subtask #1
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 8280 KB Output is correct
2 Correct 2 ms 8280 KB Output is correct
3 Correct 2 ms 8280 KB Output is correct
4 Correct 2 ms 8284 KB Output is correct
5 Correct 2 ms 8284 KB Output is correct
6 Correct 2 ms 8284 KB Output is correct
7 Correct 2 ms 8280 KB Output is correct
8 Correct 2 ms 8284 KB Output is correct
9 Correct 2 ms 8284 KB Output is correct
10 Correct 3 ms 8284 KB Output is correct

Subtask #2
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 123 ms 16820 KB Output is correct
2 Correct 161 ms 19560 KB Output is correct
3 Correct 88 ms 13528 KB Output is correct
4 Correct 73 ms 12608 KB Output is correct
5 Correct 172 ms 19776 KB Output is correct

Subtask #3
0.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 1 ms 348 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 1 ms 348 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #5
0.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 1 ms 344 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #6
0.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 8280 KB Output is correct
2 Correct 2 ms 8280 KB Output is correct
3 Correct 2 ms 8280 KB Output is correct
4 Correct 2 ms 8284 KB Output is correct
5 Correct 2 ms 8284 KB Output is correct
6 Correct 2 ms 8284 KB Output is correct
7 Correct 2 ms 8280 KB Output is correct
8 Correct 2 ms 8284 KB Output is correct
9 Correct 2 ms 8284 KB Output is correct
10 Correct 3 ms 8284 KB Output is correct
11 Correct 123 ms 16820 KB Output is correct
12 Correct 161 ms 19560 KB Output is correct
13 Correct 88 ms 13528 KB Output is correct
14 Correct 73 ms 12608 KB Output is correct
15 Correct 172 ms 19776 KB Output is correct
16 Incorrect 1 ms 348 KB Output isn't correct
17 Halted 0 ms 0 KB -