oj.uz

Submission #640392

# Submission time Handle Problem Language Result Execution time Memory
640392 2022-09-14T14:14:11 Z chenwz Parking (CEOI22_parking) C++11
100 / 100
 453 ms 85368 KB 
#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> pi;
const int MAXN = 400005;

int b[MAXN], t[MAXN], fa[MAXN], siz[MAXN], InCycle[MAXN], TPCnt[MAXN],
    cnt[MAXN];
set<int> Free, G[MAXN];
vector<int> Loc[MAXN];
vector<pair<pi, int> > red;
vector<pi> sol;
void move(int x, int y) {
  sol.push_back({x, y});
  if (++cnt[y] == 1) Free.erase(y);
  if (--cnt[x] == 0) Free.insert(x);
}
int find_set(int x) { return x == fa[x] ? x : fa[x] = find_set(fa[x]); }
void add_edge(int x, int y) {
  G[x].insert(y), G[y].insert(x);
  TPCnt[y] += (x % 2) && (y % 2);
  x = find_set(x), y = find_set(y);
  if (x == y)
    InCycle[x] = 1;
  else
    fa[x] = y, siz[y] += siz[x], TPCnt[y] += TPCnt[x];
}
void remove_edge(int x, int y) { G[x].erase(y), G[y].erase(x); }
int get_end_of_chain(int x, int last) {
  if (G[x].size() == 1) return x;
  assert(G[x].size() == 2);
  for (auto v : G[x])
    if (v != last) return get_end_of_chain(v, x);
  return -1;
}
bool solve_path(int idx) {
  int curr = get_end_of_chain(idx, -1), last = -1;
  vector<int> r;
  while (curr != -1) {
    r.push_back(curr);
    int nxt = -1;
    for (auto v : G[curr])
      if (v != last) nxt = v;
    last = curr, curr = nxt;
  }
  for (int i = 0, sz = r.size(); i < sz; i++) {
    if (r[i + 1] % 2 == 1) {
      move(r[i + 1] / 2, r[i] / 2), i++;
      continue;
    }
    int k = -1;
    for (int j = i; j < sz - 1; j++) {
      if (r[j] % 2 == 1 && r[j + 1] % 2 == 1) {
        k = j;
        break;
      }
    }
    if (k != -1) {
      if (Free.empty()) return false;
      int to = *Free.begin();
      move(r[k] / 2, to), move(r[k + 1] / 2, to);
      for (int j = k - 1; j >= i; j -= 2) move(r[j - 1] / 2, r[j] / 2);
      i = k + 1;
    } else {
      for (int j = sz - 1; j > i + 1; j -= 2) move(r[j - 1] / 2, r[j] / 2);
      move(r[i] / 2, r[i + 1] / 2);
      break;
    }
  }
  return true;
}

bool solve_cycle(int idx) {
  if (Free.empty()) return false;
  int pocetak = idx, curr = idx, last = -1;
  vector<int> r;
  while (curr != -1) {
    r.push_back(curr);
    int nxt = -1;
    for (auto v : G[curr]) {
      if (v == last || v == pocetak) continue;
      nxt = v;
    }
    last = curr, curr = nxt;
  }
  int R = r.size(), k = -1;
  for (int i = 0; i < R; i++) {
    if (r[i] % 2 == 1) k = i;
    if (r[i] % 2 == 1 && r[(i + 1) % R] % 2 == 1) {
      k = i;
      break;
    }
  }
  int x = r[k], y = r[(k + 1) % R];
  if (y % 2 == 1) {
    int to = *Free.begin();
    move(x / 2, to), move(y / 2, to);
    remove_edge(r[(k - 1 + R) % R], r[k]);
    remove_edge(r[k], r[(k + 1) % R]);
    remove_edge(r[(k + 1) % R], r[(k + 2) % R]);
    solve_path(r[(k + 2) % r.size()]);
  } else {
    int to = *Free.begin();
    if (x / 2 != y / 2) {
      move(x / 2, to);
      for (int i = 2; i < R; i += 2)
        move(r[(k - i + R) % R] / 2, r[(k - i + 1 + R) % R] / 2);
      move(y / 2, to);
    } else {
      move(x / 2, to);
      for (int i = 1; i + 1 < R; i += 2)
        move(r[(k + i + 1) % R] / 2, r[(k + i) % R] / 2);
      move(r[(k - 1 + R) % R] / 2, to);
    }
  }
  return true;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < m; i++) {
    cin >> b[i] >> t[i];
    if (b[i]) Loc[b[i]].push_back(2 * i);
    if (t[i]) Loc[t[i]].push_back(2 * i + 1);
    fa[2 * i] = 2 * i, siz[2 * i] = 1;
    fa[2 * i + 1] = 2 * i + 1, siz[2 * i + 1] = 1;
    cnt[i] = (b[i] > 0) + (t[i] > 0);
    if (cnt[i] == 0) Free.insert(i);
  }

  for (int i = 1; i <= n; i++) {
    int x = Loc[i][0], y = Loc[i][1];
    if (x / 2 != y / 2) add_edge(x, y);
  }
  for (int i = 0; i < m; i++)
    if (b[i] && t[i] && b[i] != t[i]) add_edge(2 * i, 2 * i + 1);
  for (int i = 0; i < 2 * m; i++)
    if (i == fa[i] && siz[i] > 1) red.push_back({{InCycle[i], TPCnt[i]}, i});
  sort(red.begin(), red.end());
  bool suc = true;
  for (auto p : red) {
    int idx = p.second;
    suc = !InCycle[idx] ? solve_path(idx) : solve_cycle(idx);
    if (!suc) break;
  }
  if (!suc) {
    cout << -1 << '\n';
  } else {
    cout << sol.size() << endl;
    for (auto p : sol) cout << p.first + 1 << " " << p.second + 1 << '\n';
  }
  return 0;
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 28500 KB Output is correct
2 Correct 15 ms 28508 KB Output is correct
3 Correct 15 ms 28500 KB Output is correct
4 Correct 14 ms 28500 KB Output is correct
5 Correct 13 ms 28500 KB Output is correct
6 Correct 17 ms 28500 KB Output is correct
7 Correct 14 ms 28500 KB Output is correct
8 Correct 14 ms 28544 KB Output is correct
9 Correct 15 ms 28524 KB Output is correct
10 Correct 14 ms 28500 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 187 ms 55868 KB Output is correct
2 Correct 216 ms 59328 KB Output is correct
3 Correct 146 ms 52288 KB Output is correct
4 Correct 139 ms 51496 KB Output is correct
5 Correct 231 ms 59240 KB Output is correct

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 28720 KB Output is correct
2 Correct 14 ms 28500 KB Output is correct
3 Correct 19 ms 28700 KB Output is correct
4 Correct 18 ms 28756 KB Output is correct
5 Correct 16 ms 28756 KB Output is correct
6 Correct 15 ms 28716 KB Output is correct
7 Correct 15 ms 28756 KB Output is correct
8 Correct 15 ms 28780 KB Output is correct
9 Correct 15 ms 28756 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 28720 KB Output is correct
2 Correct 14 ms 28500 KB Output is correct
3 Correct 19 ms 28700 KB Output is correct
4 Correct 18 ms 28756 KB Output is correct
5 Correct 16 ms 28756 KB Output is correct
6 Correct 15 ms 28716 KB Output is correct
7 Correct 15 ms 28756 KB Output is correct
8 Correct 15 ms 28780 KB Output is correct
9 Correct 15 ms 28756 KB Output is correct
10 Correct 428 ms 85368 KB Output is correct
11 Correct 74 ms 39884 KB Output is correct
12 Correct 294 ms 78216 KB Output is correct
13 Correct 401 ms 82636 KB Output is correct
14 Correct 303 ms 80256 KB Output is correct
15 Correct 285 ms 78352 KB Output is correct
16 Correct 453 ms 85228 KB Output is correct
17 Correct 353 ms 78916 KB Output is correct
18 Correct 434 ms 84492 KB Output is correct

Subtask #5
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 28696 KB Output is correct
2 Correct 15 ms 28756 KB Output is correct
3 Correct 15 ms 28772 KB Output is correct
4 Correct 15 ms 28712 KB Output is correct
5 Correct 14 ms 28528 KB Output is correct
6 Correct 15 ms 28740 KB Output is correct
7 Correct 15 ms 28756 KB Output is correct
8 Correct 16 ms 28756 KB Output is correct
9 Correct 17 ms 28696 KB Output is correct
10 Correct 15 ms 28756 KB Output is correct
11 Correct 16 ms 28844 KB Output is correct
12 Correct 16 ms 28760 KB Output is correct
13 Correct 15 ms 28756 KB Output is correct
14 Correct 15 ms 28896 KB Output is correct
15 Correct 16 ms 28696 KB Output is correct
16 Correct 15 ms 28796 KB Output is correct
17 Correct 15 ms 28812 KB Output is correct
18 Correct 17 ms 28884 KB Output is correct
19 Correct 15 ms 28748 KB Output is correct
20 Correct 15 ms 28756 KB Output is correct
21 Correct 15 ms 28756 KB Output is correct
22 Correct 16 ms 28756 KB Output is correct
23 Correct 15 ms 28820 KB Output is correct
24 Correct 15 ms 28756 KB Output is correct

Subtask #6
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 28500 KB Output is correct
2 Correct 15 ms 28508 KB Output is correct
3 Correct 15 ms 28500 KB Output is correct
4 Correct 14 ms 28500 KB Output is correct
5 Correct 13 ms 28500 KB Output is correct
6 Correct 17 ms 28500 KB Output is correct
7 Correct 14 ms 28500 KB Output is correct
8 Correct 14 ms 28544 KB Output is correct
9 Correct 15 ms 28524 KB Output is correct
10 Correct 14 ms 28500 KB Output is correct
11 Correct 187 ms 55868 KB Output is correct
12 Correct 216 ms 59328 KB Output is correct
13 Correct 146 ms 52288 KB Output is correct
14 Correct 139 ms 51496 KB Output is correct
15 Correct 231 ms 59240 KB Output is correct
16 Correct 15 ms 28720 KB Output is correct
17 Correct 14 ms 28500 KB Output is correct
18 Correct 19 ms 28700 KB Output is correct
19 Correct 18 ms 28756 KB Output is correct
20 Correct 16 ms 28756 KB Output is correct
21 Correct 15 ms 28716 KB Output is correct
22 Correct 15 ms 28756 KB Output is correct
23 Correct 15 ms 28780 KB Output is correct
24 Correct 15 ms 28756 KB Output is correct
25 Correct 428 ms 85368 KB Output is correct
26 Correct 74 ms 39884 KB Output is correct
27 Correct 294 ms 78216 KB Output is correct
28 Correct 401 ms 82636 KB Output is correct
29 Correct 303 ms 80256 KB Output is correct
30 Correct 285 ms 78352 KB Output is correct
31 Correct 453 ms 85228 KB Output is correct
32 Correct 353 ms 78916 KB Output is correct
33 Correct 434 ms 84492 KB Output is correct
34 Correct 15 ms 28696 KB Output is correct
35 Correct 15 ms 28756 KB Output is correct
36 Correct 15 ms 28772 KB Output is correct
37 Correct 15 ms 28712 KB Output is correct
38 Correct 14 ms 28528 KB Output is correct
39 Correct 15 ms 28740 KB Output is correct
40 Correct 15 ms 28756 KB Output is correct
41 Correct 16 ms 28756 KB Output is correct
42 Correct 17 ms 28696 KB Output is correct
43 Correct 15 ms 28756 KB Output is correct
44 Correct 16 ms 28844 KB Output is correct
45 Correct 16 ms 28760 KB Output is correct
46 Correct 15 ms 28756 KB Output is correct
47 Correct 15 ms 28896 KB Output is correct
48 Correct 16 ms 28696 KB Output is correct
49 Correct 15 ms 28796 KB Output is correct
50 Correct 15 ms 28812 KB Output is correct
51 Correct 17 ms 28884 KB Output is correct
52 Correct 15 ms 28748 KB Output is correct
53 Correct 15 ms 28756 KB Output is correct
54 Correct 15 ms 28756 KB Output is correct
55 Correct 16 ms 28756 KB Output is correct
56 Correct 15 ms 28820 KB Output is correct
57 Correct 15 ms 28756 KB Output is correct
58 Correct 390 ms 77760 KB Output is correct
59 Correct 421 ms 83016 KB Output is correct
60 Correct 333 ms 72144 KB Output is correct
61 Correct 390 ms 80372 KB Output is correct
62 Correct 81 ms 40136 KB Output is correct
63 Correct 408 ms 81180 KB Output is correct
64 Correct 305 ms 78808 KB Output is correct
65 Correct 407 ms 81764 KB Output is correct
66 Correct 433 ms 83980 KB Output is correct
67 Correct 289 ms 77168 KB Output is correct
68 Correct 407 ms 83284 KB Output is correct
69 Correct 390 ms 81788 KB Output is correct
70 Correct 300 ms 77212 KB Output is correct
71 Correct 324 ms 79772 KB Output is correct
72 Correct 303 ms 78980 KB Output is correct
73 Correct 434 ms 85260 KB Output is correct
74 Correct 281 ms 78352 KB Output is correct
75 Correct 422 ms 83624 KB Output is correct
76 Correct 442 ms 84764 KB Output is correct
77 Correct 440 ms 83020 KB Output is correct
78 Correct 304 ms 79104 KB Output is correct
79 Correct 405 ms 82604 KB Output is correct
80 Correct 316 ms 79272 KB Output is correct
81 Correct 428 ms 83580 KB Output is correct