oj.uz

Submission #640394

# Submission time Handle Problem Language Result Execution time Memory
640394 2022-09-14T14:20:02 Z chenwz Parking (CEOI22_parking) C++11
100 / 100
 478 ms 85364 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) {
  vector<int> r;
  for (int u = get_end_of_chain(idx, -1), last = -1; u != -1;) {
    r.push_back(u);
    int nxt = -1;
    for (auto v : G[u]) {
      if (v == last) continue;
      nxt = v;
    }
    last = u, u = 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 15 ms 28500 KB Output is correct
2 Correct 17 ms 28480 KB Output is correct
3 Correct 14 ms 28524 KB Output is correct
4 Correct 14 ms 28500 KB Output is correct
5 Correct 16 ms 28440 KB Output is correct
6 Correct 14 ms 28500 KB Output is correct
7 Correct 14 ms 28500 KB Output is correct
8 Correct 14 ms 28500 KB Output is correct
9 Correct 14 ms 28500 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 214 ms 55776 KB Output is correct
2 Correct 240 ms 59328 KB Output is correct
3 Correct 174 ms 52408 KB Output is correct
4 Correct 151 ms 51516 KB Output is correct
5 Correct 239 ms 59272 KB Output is correct

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 28648 KB Output is correct
2 Correct 15 ms 28516 KB Output is correct
3 Correct 17 ms 28756 KB Output is correct
4 Correct 15 ms 28756 KB Output is correct
5 Correct 16 ms 28696 KB Output is correct
6 Correct 15 ms 28756 KB Output is correct
7 Correct 15 ms 28756 KB Output is correct
8 Correct 19 ms 28696 KB Output is correct
9 Correct 18 ms 28744 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 28648 KB Output is correct
2 Correct 15 ms 28516 KB Output is correct
3 Correct 17 ms 28756 KB Output is correct
4 Correct 15 ms 28756 KB Output is correct
5 Correct 16 ms 28696 KB Output is correct
6 Correct 15 ms 28756 KB Output is correct
7 Correct 15 ms 28756 KB Output is correct
8 Correct 19 ms 28696 KB Output is correct
9 Correct 18 ms 28744 KB Output is correct
10 Correct 476 ms 85364 KB Output is correct
11 Correct 90 ms 39900 KB Output is correct
12 Correct 317 ms 78200 KB Output is correct
13 Correct 418 ms 82688 KB Output is correct
14 Correct 334 ms 80256 KB Output is correct
15 Correct 285 ms 78324 KB Output is correct
16 Correct 478 ms 85320 KB Output is correct
17 Correct 364 ms 78780 KB Output is correct
18 Correct 430 ms 84504 KB Output is correct

Subtask #5
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 28756 KB Output is correct
2 Correct 15 ms 28760 KB Output is correct
3 Correct 19 ms 28720 KB Output is correct
4 Correct 16 ms 28672 KB Output is correct
5 Correct 15 ms 28500 KB Output is correct
6 Correct 15 ms 28732 KB Output is correct
7 Correct 15 ms 28756 KB Output is correct
8 Correct 19 ms 28756 KB Output is correct
9 Correct 15 ms 28800 KB Output is correct
10 Correct 16 ms 28756 KB Output is correct
11 Correct 18 ms 28752 KB Output is correct
12 Correct 17 ms 28772 KB Output is correct
13 Correct 15 ms 28756 KB Output is correct
14 Correct 14 ms 28724 KB Output is correct
15 Correct 19 ms 28784 KB Output is correct
16 Correct 16 ms 28780 KB Output is correct
17 Correct 16 ms 28804 KB Output is correct
18 Correct 18 ms 28740 KB Output is correct
19 Correct 15 ms 28756 KB Output is correct
20 Correct 15 ms 28812 KB Output is correct
21 Correct 17 ms 28756 KB Output is correct
22 Correct 15 ms 28756 KB Output is correct
23 Correct 15 ms 28704 KB Output is correct
24 Correct 16 ms 28832 KB Output is correct

Subtask #6
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 28500 KB Output is correct
2 Correct 17 ms 28480 KB Output is correct
3 Correct 14 ms 28524 KB Output is correct
4 Correct 14 ms 28500 KB Output is correct
5 Correct 16 ms 28440 KB Output is correct
6 Correct 14 ms 28500 KB Output is correct
7 Correct 14 ms 28500 KB Output is correct
8 Correct 14 ms 28500 KB Output is correct
9 Correct 14 ms 28500 KB Output is correct
10 Correct 14 ms 28500 KB Output is correct
11 Correct 214 ms 55776 KB Output is correct
12 Correct 240 ms 59328 KB Output is correct
13 Correct 174 ms 52408 KB Output is correct
14 Correct 151 ms 51516 KB Output is correct
15 Correct 239 ms 59272 KB Output is correct
16 Correct 15 ms 28648 KB Output is correct
17 Correct 15 ms 28516 KB Output is correct
18 Correct 17 ms 28756 KB Output is correct
19 Correct 15 ms 28756 KB Output is correct
20 Correct 16 ms 28696 KB Output is correct
21 Correct 15 ms 28756 KB Output is correct
22 Correct 15 ms 28756 KB Output is correct
23 Correct 19 ms 28696 KB Output is correct
24 Correct 18 ms 28744 KB Output is correct
25 Correct 476 ms 85364 KB Output is correct
26 Correct 90 ms 39900 KB Output is correct
27 Correct 317 ms 78200 KB Output is correct
28 Correct 418 ms 82688 KB Output is correct
29 Correct 334 ms 80256 KB Output is correct
30 Correct 285 ms 78324 KB Output is correct
31 Correct 478 ms 85320 KB Output is correct
32 Correct 364 ms 78780 KB Output is correct
33 Correct 430 ms 84504 KB Output is correct
34 Correct 15 ms 28756 KB Output is correct
35 Correct 15 ms 28760 KB Output is correct
36 Correct 19 ms 28720 KB Output is correct
37 Correct 16 ms 28672 KB Output is correct
38 Correct 15 ms 28500 KB Output is correct
39 Correct 15 ms 28732 KB Output is correct
40 Correct 15 ms 28756 KB Output is correct
41 Correct 19 ms 28756 KB Output is correct
42 Correct 15 ms 28800 KB Output is correct
43 Correct 16 ms 28756 KB Output is correct
44 Correct 18 ms 28752 KB Output is correct
45 Correct 17 ms 28772 KB Output is correct
46 Correct 15 ms 28756 KB Output is correct
47 Correct 14 ms 28724 KB Output is correct
48 Correct 19 ms 28784 KB Output is correct
49 Correct 16 ms 28780 KB Output is correct
50 Correct 16 ms 28804 KB Output is correct
51 Correct 18 ms 28740 KB Output is correct
52 Correct 15 ms 28756 KB Output is correct
53 Correct 15 ms 28812 KB Output is correct
54 Correct 17 ms 28756 KB Output is correct
55 Correct 15 ms 28756 KB Output is correct
56 Correct 15 ms 28704 KB Output is correct
57 Correct 16 ms 28832 KB Output is correct
58 Correct 405 ms 77688 KB Output is correct
59 Correct 436 ms 83092 KB Output is correct
60 Correct 347 ms 72204 KB Output is correct
61 Correct 409 ms 80388 KB Output is correct
62 Correct 89 ms 40140 KB Output is correct
63 Correct 426 ms 81240 KB Output is correct
64 Correct 389 ms 78880 KB Output is correct
65 Correct 425 ms 81872 KB Output is correct
66 Correct 468 ms 84028 KB Output is correct
67 Correct 290 ms 77168 KB Output is correct
68 Correct 408 ms 83244 KB Output is correct
69 Correct 445 ms 81708 KB Output is correct
70 Correct 346 ms 77260 KB Output is correct
71 Correct 299 ms 79740 KB Output is correct
72 Correct 315 ms 78932 KB Output is correct
73 Correct 460 ms 85216 KB Output is correct
74 Correct 335 ms 78248 KB Output is correct
75 Correct 439 ms 83628 KB Output is correct
76 Correct 445 ms 84632 KB Output is correct
77 Correct 436 ms 83128 KB Output is correct
78 Correct 350 ms 78920 KB Output is correct
79 Correct 470 ms 82496 KB Output is correct
80 Correct 335 ms 79232 KB Output is correct
81 Correct 419 ms 83496 KB Output is correct