oj.uz

Submission #640390

# Submission time Handle Problem Language Result Execution time Memory
640390 2022-09-14T14:08:26 Z chenwz Parking (CEOI22_parking) C++11
100 / 100
 490 ms 85936 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) continue;
      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++;
    } else {
      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:157:21: 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]
  157 |   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 14 ms 28508 KB Output is correct
3 Correct 14 ms 28500 KB Output is correct
4 Correct 15 ms 28500 KB Output is correct
5 Correct 17 ms 28544 KB Output is correct
6 Correct 16 ms 28444 KB Output is correct
7 Correct 19 ms 28500 KB Output is correct
8 Correct 21 ms 28516 KB Output is correct
9 Correct 19 ms 28500 KB Output is correct
10 Correct 21 ms 28504 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 229 ms 56276 KB Output is correct
2 Correct 243 ms 59740 KB Output is correct
3 Correct 148 ms 52880 KB Output is correct
4 Correct 162 ms 52296 KB Output is correct
5 Correct 230 ms 60056 KB Output is correct

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 28756 KB Output is correct
2 Correct 15 ms 28512 KB Output is correct
3 Correct 15 ms 28756 KB Output is correct
4 Correct 16 ms 28844 KB Output is correct
5 Correct 16 ms 28708 KB Output is correct
6 Correct 17 ms 28760 KB Output is correct
7 Correct 16 ms 28752 KB Output is correct
8 Correct 18 ms 28788 KB Output is correct
9 Correct 16 ms 28764 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 28756 KB Output is correct
2 Correct 15 ms 28512 KB Output is correct
3 Correct 15 ms 28756 KB Output is correct
4 Correct 16 ms 28844 KB Output is correct
5 Correct 16 ms 28708 KB Output is correct
6 Correct 17 ms 28760 KB Output is correct
7 Correct 16 ms 28752 KB Output is correct
8 Correct 18 ms 28788 KB Output is correct
9 Correct 16 ms 28764 KB Output is correct
10 Correct 457 ms 85612 KB Output is correct
11 Correct 86 ms 39992 KB Output is correct
12 Correct 314 ms 78468 KB Output is correct
13 Correct 453 ms 83120 KB Output is correct
14 Correct 344 ms 80600 KB Output is correct
15 Correct 302 ms 78908 KB Output is correct
16 Correct 454 ms 85936 KB Output is correct
17 Correct 346 ms 79320 KB Output is correct
18 Correct 490 ms 85008 KB Output is correct

Subtask #5
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 20 ms 28772 KB Output is correct
2 Correct 19 ms 28768 KB Output is correct
3 Correct 16 ms 28688 KB Output is correct
4 Correct 15 ms 28628 KB Output is correct
5 Correct 15 ms 28524 KB Output is correct
6 Correct 17 ms 28772 KB Output is correct
7 Correct 15 ms 28756 KB Output is correct
8 Correct 15 ms 28756 KB Output is correct
9 Correct 15 ms 28756 KB Output is correct
10 Correct 15 ms 28788 KB Output is correct
11 Correct 17 ms 28756 KB Output is correct
12 Correct 16 ms 28716 KB Output is correct
13 Correct 15 ms 28756 KB Output is correct
14 Correct 15 ms 28804 KB Output is correct
15 Correct 16 ms 28748 KB Output is correct
16 Correct 19 ms 28756 KB Output is correct
17 Correct 16 ms 28692 KB Output is correct
18 Correct 16 ms 28788 KB Output is correct
19 Correct 15 ms 28748 KB Output is correct
20 Correct 17 ms 28756 KB Output is correct
21 Correct 16 ms 28756 KB Output is correct
22 Correct 16 ms 28756 KB Output is correct
23 Correct 15 ms 28756 KB Output is correct
24 Correct 16 ms 28756 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 14 ms 28508 KB Output is correct
3 Correct 14 ms 28500 KB Output is correct
4 Correct 15 ms 28500 KB Output is correct
5 Correct 17 ms 28544 KB Output is correct
6 Correct 16 ms 28444 KB Output is correct
7 Correct 19 ms 28500 KB Output is correct
8 Correct 21 ms 28516 KB Output is correct
9 Correct 19 ms 28500 KB Output is correct
10 Correct 21 ms 28504 KB Output is correct
11 Correct 229 ms 56276 KB Output is correct
12 Correct 243 ms 59740 KB Output is correct
13 Correct 148 ms 52880 KB Output is correct
14 Correct 162 ms 52296 KB Output is correct
15 Correct 230 ms 60056 KB Output is correct
16 Correct 15 ms 28756 KB Output is correct
17 Correct 15 ms 28512 KB Output is correct
18 Correct 15 ms 28756 KB Output is correct
19 Correct 16 ms 28844 KB Output is correct
20 Correct 16 ms 28708 KB Output is correct
21 Correct 17 ms 28760 KB Output is correct
22 Correct 16 ms 28752 KB Output is correct
23 Correct 18 ms 28788 KB Output is correct
24 Correct 16 ms 28764 KB Output is correct
25 Correct 457 ms 85612 KB Output is correct
26 Correct 86 ms 39992 KB Output is correct
27 Correct 314 ms 78468 KB Output is correct
28 Correct 453 ms 83120 KB Output is correct
29 Correct 344 ms 80600 KB Output is correct
30 Correct 302 ms 78908 KB Output is correct
31 Correct 454 ms 85936 KB Output is correct
32 Correct 346 ms 79320 KB Output is correct
33 Correct 490 ms 85008 KB Output is correct
34 Correct 20 ms 28772 KB Output is correct
35 Correct 19 ms 28768 KB Output is correct
36 Correct 16 ms 28688 KB Output is correct
37 Correct 15 ms 28628 KB Output is correct
38 Correct 15 ms 28524 KB Output is correct
39 Correct 17 ms 28772 KB Output is correct
40 Correct 15 ms 28756 KB Output is correct
41 Correct 15 ms 28756 KB Output is correct
42 Correct 15 ms 28756 KB Output is correct
43 Correct 15 ms 28788 KB Output is correct
44 Correct 17 ms 28756 KB Output is correct
45 Correct 16 ms 28716 KB Output is correct
46 Correct 15 ms 28756 KB Output is correct
47 Correct 15 ms 28804 KB Output is correct
48 Correct 16 ms 28748 KB Output is correct
49 Correct 19 ms 28756 KB Output is correct
50 Correct 16 ms 28692 KB Output is correct
51 Correct 16 ms 28788 KB Output is correct
52 Correct 15 ms 28748 KB Output is correct
53 Correct 17 ms 28756 KB Output is correct
54 Correct 16 ms 28756 KB Output is correct
55 Correct 16 ms 28756 KB Output is correct
56 Correct 15 ms 28756 KB Output is correct
57 Correct 16 ms 28756 KB Output is correct
58 Correct 394 ms 78280 KB Output is correct
59 Correct 428 ms 83904 KB Output is correct
60 Correct 354 ms 73156 KB Output is correct
61 Correct 416 ms 81252 KB Output is correct
62 Correct 92 ms 41212 KB Output is correct
63 Correct 424 ms 81904 KB Output is correct
64 Correct 418 ms 79468 KB Output is correct
65 Correct 462 ms 82624 KB Output is correct
66 Correct 470 ms 84596 KB Output is correct
67 Correct 310 ms 78032 KB Output is correct
68 Correct 414 ms 83972 KB Output is correct
69 Correct 403 ms 82196 KB Output is correct
70 Correct 352 ms 77856 KB Output is correct
71 Correct 348 ms 80012 KB Output is correct
72 Correct 306 ms 79528 KB Output is correct
73 Correct 489 ms 85772 KB Output is correct
74 Correct 343 ms 78832 KB Output is correct
75 Correct 425 ms 84116 KB Output is correct
76 Correct 427 ms 85176 KB Output is correct
77 Correct 428 ms 83256 KB Output is correct
78 Correct 376 ms 78980 KB Output is correct
79 Correct 435 ms 82776 KB Output is correct
80 Correct 336 ms 80228 KB Output is correct
81 Correct 444 ms 83724 KB Output is correct