oj.uz

Submission #640391

# Submission time Handle Problem Language Result Execution time Memory
640391 2022-09-14T14:10:03 Z chenwz Parking (CEOI22_parking) C++11
100 / 100
 544 ms 85384 KB 
#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> pi;
const int MAXN = 400005;
int n, m, moze = 1;
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;
}
void 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()) {
        moze = 0;
        return;
      }
      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;
    }
  }
}

void solve_cycle(int idx) {
  if (Free.size() == 0) {
    moze = 0;
    return;
  }
  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();

  int 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);
    }
  }
}

void ispis() {}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  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());
  for (int i = 0; i < red.size(); i++) {
    int idx = red[i].second;
    if (!InCycle[idx])
      solve_path(idx);
    else
      solve_cycle(idx);
  }
  if (moze == 0) {
    cout << -1 << '\n';
  } else {
    cout << sol.size() << endl;
    for (auto pp : sol) cout << pp.first + 1 << " " << pp.second + 1 << '\n';
  }
  return 0;
}

Compilation message

Main.cpp: In function 'int main()':
Main.cpp:153:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<std::pair<int, int>, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  153 |   for (int i = 0; i < red.size(); i++) {
      |                   ~~^~~~~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 28500 KB Output is correct
2 Correct 14 ms 28532 KB Output is correct
3 Correct 15 ms 28512 KB Output is correct
4 Correct 16 ms 28472 KB Output is correct
5 Correct 14 ms 28476 KB Output is correct
6 Correct 14 ms 28480 KB Output is correct
7 Correct 15 ms 28500 KB Output is correct
8 Correct 14 ms 28536 KB Output is correct
9 Correct 14 ms 28504 KB Output is correct
10 Correct 16 ms 28440 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 204 ms 55900 KB Output is correct
2 Correct 219 ms 59328 KB Output is correct
3 Correct 175 ms 52300 KB Output is correct
4 Correct 178 ms 51480 KB Output is correct
5 Correct 254 ms 59196 KB Output is correct

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 28756 KB Output is correct
2 Correct 14 ms 28500 KB Output is correct
3 Correct 15 ms 28804 KB Output is correct
4 Correct 15 ms 28756 KB Output is correct
5 Correct 14 ms 28756 KB Output is correct
6 Correct 15 ms 28756 KB Output is correct
7 Correct 15 ms 28756 KB Output is correct
8 Correct 16 ms 28772 KB Output is correct
9 Correct 14 ms 28756 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 28756 KB Output is correct
2 Correct 14 ms 28500 KB Output is correct
3 Correct 15 ms 28804 KB Output is correct
4 Correct 15 ms 28756 KB Output is correct
5 Correct 14 ms 28756 KB Output is correct
6 Correct 15 ms 28756 KB Output is correct
7 Correct 15 ms 28756 KB Output is correct
8 Correct 16 ms 28772 KB Output is correct
9 Correct 14 ms 28756 KB Output is correct
10 Correct 448 ms 85384 KB Output is correct
11 Correct 91 ms 39896 KB Output is correct
12 Correct 346 ms 78176 KB Output is correct
13 Correct 445 ms 82700 KB Output is correct
14 Correct 303 ms 80204 KB Output is correct
15 Correct 345 ms 78292 KB Output is correct
16 Correct 544 ms 85272 KB Output is correct
17 Correct 423 ms 78976 KB Output is correct
18 Correct 449 ms 84692 KB Output is correct

Subtask #5
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 28796 KB Output is correct
2 Correct 16 ms 28712 KB Output is correct
3 Correct 18 ms 28772 KB Output is correct
4 Correct 16 ms 28628 KB Output is correct
5 Correct 16 ms 28512 KB Output is correct
6 Correct 16 ms 28756 KB Output is correct
7 Correct 16 ms 28708 KB Output is correct
8 Correct 16 ms 28756 KB Output is correct
9 Correct 18 ms 28756 KB Output is correct
10 Correct 17 ms 28736 KB Output is correct
11 Correct 16 ms 28756 KB Output is correct
12 Correct 17 ms 28756 KB Output is correct
13 Correct 14 ms 28756 KB Output is correct
14 Correct 16 ms 28756 KB Output is correct
15 Correct 15 ms 28812 KB Output is correct
16 Correct 19 ms 28732 KB Output is correct
17 Correct 16 ms 28720 KB Output is correct
18 Correct 19 ms 28756 KB Output is correct
19 Correct 15 ms 28736 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 28728 KB Output is correct
23 Correct 15 ms 28692 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 14 ms 28532 KB Output is correct
3 Correct 15 ms 28512 KB Output is correct
4 Correct 16 ms 28472 KB Output is correct
5 Correct 14 ms 28476 KB Output is correct
6 Correct 14 ms 28480 KB Output is correct
7 Correct 15 ms 28500 KB Output is correct
8 Correct 14 ms 28536 KB Output is correct
9 Correct 14 ms 28504 KB Output is correct
10 Correct 16 ms 28440 KB Output is correct
11 Correct 204 ms 55900 KB Output is correct
12 Correct 219 ms 59328 KB Output is correct
13 Correct 175 ms 52300 KB Output is correct
14 Correct 178 ms 51480 KB Output is correct
15 Correct 254 ms 59196 KB Output is correct
16 Correct 16 ms 28756 KB Output is correct
17 Correct 14 ms 28500 KB Output is correct
18 Correct 15 ms 28804 KB Output is correct
19 Correct 15 ms 28756 KB Output is correct
20 Correct 14 ms 28756 KB Output is correct
21 Correct 15 ms 28756 KB Output is correct
22 Correct 15 ms 28756 KB Output is correct
23 Correct 16 ms 28772 KB Output is correct
24 Correct 14 ms 28756 KB Output is correct
25 Correct 448 ms 85384 KB Output is correct
26 Correct 91 ms 39896 KB Output is correct
27 Correct 346 ms 78176 KB Output is correct
28 Correct 445 ms 82700 KB Output is correct
29 Correct 303 ms 80204 KB Output is correct
30 Correct 345 ms 78292 KB Output is correct
31 Correct 544 ms 85272 KB Output is correct
32 Correct 423 ms 78976 KB Output is correct
33 Correct 449 ms 84692 KB Output is correct
34 Correct 17 ms 28796 KB Output is correct
35 Correct 16 ms 28712 KB Output is correct
36 Correct 18 ms 28772 KB Output is correct
37 Correct 16 ms 28628 KB Output is correct
38 Correct 16 ms 28512 KB Output is correct
39 Correct 16 ms 28756 KB Output is correct
40 Correct 16 ms 28708 KB Output is correct
41 Correct 16 ms 28756 KB Output is correct
42 Correct 18 ms 28756 KB Output is correct
43 Correct 17 ms 28736 KB Output is correct
44 Correct 16 ms 28756 KB Output is correct
45 Correct 17 ms 28756 KB Output is correct
46 Correct 14 ms 28756 KB Output is correct
47 Correct 16 ms 28756 KB Output is correct
48 Correct 15 ms 28812 KB Output is correct
49 Correct 19 ms 28732 KB Output is correct
50 Correct 16 ms 28720 KB Output is correct
51 Correct 19 ms 28756 KB Output is correct
52 Correct 15 ms 28736 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 28728 KB Output is correct
56 Correct 15 ms 28692 KB Output is correct
57 Correct 15 ms 28756 KB Output is correct
58 Correct 387 ms 77888 KB Output is correct
59 Correct 431 ms 83012 KB Output is correct
60 Correct 345 ms 72260 KB Output is correct
61 Correct 420 ms 80532 KB Output is correct
62 Correct 86 ms 40280 KB Output is correct
63 Correct 399 ms 81256 KB Output is correct
64 Correct 389 ms 78940 KB Output is correct
65 Correct 418 ms 81904 KB Output is correct
66 Correct 448 ms 84168 KB Output is correct
67 Correct 302 ms 77228 KB Output is correct
68 Correct 422 ms 83436 KB Output is correct
69 Correct 408 ms 81684 KB Output is correct
70 Correct 329 ms 77376 KB Output is correct
71 Correct 331 ms 79976 KB Output is correct
72 Correct 307 ms 79244 KB Output is correct
73 Correct 440 ms 85272 KB Output is correct
74 Correct 323 ms 78456 KB Output is correct
75 Correct 451 ms 83788 KB Output is correct
76 Correct 486 ms 84728 KB Output is correct
77 Correct 434 ms 83092 KB Output is correct
78 Correct 387 ms 79040 KB Output is correct
79 Correct 481 ms 82732 KB Output is correct
80 Correct 335 ms 79384 KB Output is correct
81 Correct 460 ms 83624 KB Output is correct