oj.uz

Submission #968763

# Submission time Handle Problem Language Result Execution time Memory
968763 2024-04-24T03:56:46 Z marvinthang Parking (CEOI22_parking) C++17
100 / 100
 288 ms 45480 KB 
/*************************************
*    author: marvinthang             *
*    created: 24.04.2024 10:00:00    *
*************************************/

#include <bits/stdc++.h>

using namespace std;

#define                  fi  first
#define                  se  second
#define                left  ___left
#define               right  ___right
#define                TIME  (1.0 * clock() / CLOCKS_PER_SEC)
#define             MASK(i)  (1LL << (i))
#define           BIT(x, i)  ((x) >> (i) & 1)
#define  __builtin_popcount  __builtin_popcountll
#define              ALL(v)  (v).begin(), (v).end()
#define           REP(i, n)  for (int i = 0, _n = (n); i < _n; ++i)
#define          REPD(i, n)  for (int i = (n); i-- > 0; )
#define        FOR(i, a, b)  for (int i = (a), _b = (b); i < _b; ++i) 
#define       FORD(i, b, a)  for (int i = (b), _a = (a); --i >= _a; ) 
#define       FORE(i, a, b)  for (int i = (a), _b = (b); i <= _b; ++i) 
#define      FORDE(i, b, a)  for (int i = (b), _a = (a); i >= _a; --i) 
#define        scan_op(...)  istream & operator >> (istream &in, __VA_ARGS__ &u)
#define       print_op(...)  ostream & operator << (ostream &out, const __VA_ARGS__ &u)
#ifdef LOCAL
    #include "debug.h"
#else
    #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
    #define DB(...) 23
    #define db(...) 23
    #define debug(...) 23
#endif

template <class U, class V> scan_op(pair <U, V>)  { return in >> u.first >> u.second; }
template <class T> scan_op(vector <T>)  { for (size_t i = 0; i < u.size(); ++i) in >> u[i]; return in; }
template <class U, class V> print_op(pair <U, V>)  { return out << '(' << u.first << ", " << u.second << ')'; }
template <size_t i, class T> ostream & print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")";  else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
template <class ...U> print_op(tuple<U...>) { return print_tuple_utils<0, tuple<U...>>(out, u); }
template <class Con, class = decltype(begin(declval<Con>()))> typename enable_if <!is_same<Con, string>::value, ostream&>::type operator << (ostream &out, const Con &con) { out << '{'; for (__typeof(con.begin()) it = con.begin(); it != con.end(); ++it) out << (it == con.begin() ? "" : ", ") << *it; return out << '}'; }

// end of template

void process(void) {
	int n, m; cin >> n >> m;
	vector <int> bot(m), top(m);
	vector pos(n + 1, vector(2, -1));
	vector <vector <int>> adj(m << 1);
	vector <int> emp;
	vector <int> sz(m);
	REP(i, m) {
		cin >> bot[i] >> top[i];
		if (bot[i]) {
			++sz[i];
			pos[bot[i]][pos[bot[i]][0] != -1] = i << 1;
			if (top[i]) {
				++sz[i];
				pos[top[i]][pos[top[i]][0] != -1] = i << 1 | 1;
				if (bot[i] != top[i]) {
					adj[i << 1].push_back(i << 1 | 1);
					adj[i << 1 | 1].push_back(i << 1);
				}
			}
		} else emp.push_back(i);
	}
	auto get_empty = [&] {
		while (!emp.empty() && sz[emp.back()]) emp.pop_back();
		if (emp.empty()) {
			cout << "-1\n";
			exit(0);
		}
		return emp.back();
	};
	FORE(i, 1, n) if (pos[i][0] != (pos[i][1] ^ 1)) {
		adj[pos[i][0]].push_back(pos[i][1]);
		adj[pos[i][1]].push_back(pos[i][0]);
	}
	vector <pair <int, int>> res;
	auto move = [&] (int x, int y) {
		x >>= 1; y >>= 1;
		res.emplace_back(x, y);
		if (!--sz[x]) emp.push_back(x);
		++sz[y];
	};
	auto solve_path = [&] (vector <int> &path) {
		for (int i = 0; i < (int) path.size(); i += 2) {
			if (path[i + 1] & 1) move(path[i + 1], path[i]);
			else {
				int p = path.size();
				for (int j = i; j < (int) path.size(); j += 2) if ((path[j] & 1) && (path[j + 1] & 1)) {
					p = j;
					break;
				}
				if (p < (int) path.size()) {
					int x = get_empty() << 1;
					move(path[p], x);
					move(path[p + 1], x);
				}
				for (int j = p - 2; j >= i; j -= 2) move(path[j], path[j + 1]);
				i = p;
			}
		}
	};
	vector <bool> used(m << 1);
	vector <vector <int>> paths, cycles;
	vector <int> cnt_pt;
	REP(i, m + m) if (!used[i] && (int) adj[i].size() == 1) {
		used[i] = true;
		vector <int> path {i};
		int u = i, p = -1;
		while (p == -1 || (int) adj[u].size() == 2) {
			tie(p, u) = pair{u, adj[u][adj[u][0] == p]};
			used[u] = true;
			path.push_back(u);
		}
		int cnt = 0;
		for (int i = 0; i < (int) path.size(); i += 2) if ((path[i] & 1) && (path[i + 1] & 1)) ++cnt;
		paths.push_back(path);
		cnt_pt.push_back(cnt);
	}
	vector <int> order(paths.size());
	iota(ALL(order), 0);
	sort(ALL(order), [&] (int x, int y) { return cnt_pt[x] < cnt_pt[y]; });
	for (int i: order) solve_path(paths[i]);
	auto del_edge = [&] (int x, int y) {
		adj[x].erase(find(ALL(adj[x]), y));
		adj[y].erase(find(ALL(adj[y]), x));
	};
	auto solve_cycle = [&] (vector <int> &cycle) {
		int p = -1;
		for (int i = 0; i + 1 < (int) cycle.size(); ++i) if ((cycle[i] & 1) && (cycle[i + 1] & 1)) {
			p = i;
			break;
		}
		if (p != -1) {
			int x = get_empty() << 1;
			move(cycle[p], x);
			move(cycle[p + 1], x);
			del_edge(!p ? cycle.end()[-2] : cycle[p - 1], cycle[p]);
			del_edge(cycle[p], cycle[p + 1]);
			del_edge(cycle[p + 1], p + 2 == (int) cycle.size() ? cycle[1] : cycle[p + 2]);
			cycle.pop_back();
			cycle.erase(cycle.begin() + p);
			if (p == (int) cycle.size()) cycle.erase(cycle.begin());
			else cycle.erase(cycle.begin() + p);
			rotate(cycle.begin(), cycle.begin() + p, cycle.end());
			solve_path(cycle);
		} else {
			cycle.pop_back();
			if (cycle[0] & 1) rotate(cycle.begin(), cycle.begin() + 1, cycle.end());
			if (cycle[0] == (cycle[1] ^ 1)) {
				rotate(cycle.begin(), cycle.begin() + 1, cycle.end());
				reverse(ALL(cycle));
			}
			int x = get_empty() << 1;
			move(cycle.back(), x);
			for (int i = 1; i + 2 < (int) cycle.size(); i += 2) move(cycle[i], cycle[i - 1]);
			move(cycle.end()[-2], x);
		}
	};
	REP(i, m + m) if (!used[i] && (int) adj[i].size() == 2) {
		vector <int> cycle;
		int u = i, p = -1;
		while (!used[u]) {
			used[u] = true;
			cycle.push_back(u);
			tie(p, u) = pair{u, adj[u][adj[u][0] == p]};
		}
		int cnt = 0;
		cycle.push_back(cycle[0]);
		for (int i = 0; i + 1 < (int) cycle.size(); ++i) if ((cycle[i] & 1) && (cycle[i + 1] & 1)) ++cnt;
		cycles.push_back(cycle);
		cnt_pt.push_back(cnt);
	}
	order.resize(cycles.size());
	iota(ALL(order), 0);
	sort(ALL(order), [&] (int x, int y) { return cnt_pt[x] < cnt_pt[y]; });
	for (int i: order) solve_cycle(cycles[i]);

	cout << res.size() << '\n';
	for (auto [x, y]: res) cout << x + 1 << ' ' << y + 1 << '\n';
}

int main(void) {
	ios_base::sync_with_stdio(false); cin.tie(nullptr); // cout.tie(nullptr);
	file("parking");
	// int t; cin >> t; while (t--)
	process();
	// cerr << "Time elapsed: " << TIME << " s.\n";
	return (0^0);
}

Compilation message

Main.cpp: In function 'int main()':
Main.cpp:30:61: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:187:2: note: in expansion of macro 'file'
  187 |  file("parking");
      |  ^~~~
Main.cpp:30:94: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                                                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:187:2: note: in expansion of macro 'file'
  187 |  file("parking");
      |  ^~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 344 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 1 ms 344 KB Output is correct
5 Correct 0 ms 344 KB Output is correct
6 Correct 1 ms 344 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 0 ms 344 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 600 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 85 ms 28644 KB Output is correct
2 Correct 104 ms 31360 KB Output is correct
3 Correct 65 ms 24556 KB Output is correct
4 Correct 62 ms 23872 KB Output is correct
5 Correct 98 ms 31616 KB Output is correct

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 856 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 604 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Correct 1 ms 600 KB Output is correct
7 Correct 1 ms 600 KB Output is correct
8 Correct 1 ms 600 KB Output is correct
9 Correct 1 ms 604 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 856 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 604 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Correct 1 ms 600 KB Output is correct
7 Correct 1 ms 600 KB Output is correct
8 Correct 1 ms 600 KB Output is correct
9 Correct 1 ms 604 KB Output is correct
10 Correct 272 ms 45480 KB Output is correct
11 Correct 54 ms 24908 KB Output is correct
12 Correct 187 ms 38580 KB Output is correct
13 Correct 210 ms 42956 KB Output is correct
14 Correct 200 ms 39736 KB Output is correct
15 Correct 171 ms 38228 KB Output is correct
16 Correct 260 ms 45076 KB Output is correct
17 Correct 171 ms 39140 KB Output is correct
18 Correct 262 ms 44388 KB Output is correct

Subtask #5
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 604 KB Output is correct
2 Correct 1 ms 600 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 344 KB Output is correct
5 Correct 1 ms 348 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 604 KB Output is correct
9 Correct 2 ms 604 KB Output is correct
10 Correct 1 ms 604 KB Output is correct
11 Correct 1 ms 604 KB Output is correct
12 Correct 1 ms 604 KB Output is correct
13 Correct 1 ms 604 KB Output is correct
14 Correct 1 ms 604 KB Output is correct
15 Correct 1 ms 604 KB Output is correct
16 Correct 1 ms 600 KB Output is correct
17 Correct 2 ms 600 KB Output is correct
18 Correct 1 ms 600 KB Output is correct
19 Correct 1 ms 604 KB Output is correct
20 Correct 1 ms 600 KB Output is correct
21 Correct 1 ms 600 KB Output is correct
22 Correct 1 ms 600 KB Output is correct
23 Correct 1 ms 600 KB Output is correct
24 Correct 1 ms 604 KB Output is correct

Subtask #6
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 344 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 1 ms 344 KB Output is correct
5 Correct 0 ms 344 KB Output is correct
6 Correct 1 ms 344 KB Output is correct
7 Correct 1 ms 348 KB Output is correct
8 Correct 0 ms 344 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 600 KB Output is correct
11 Correct 85 ms 28644 KB Output is correct
12 Correct 104 ms 31360 KB Output is correct
13 Correct 65 ms 24556 KB Output is correct
14 Correct 62 ms 23872 KB Output is correct
15 Correct 98 ms 31616 KB Output is correct
16 Correct 1 ms 856 KB Output is correct
17 Correct 1 ms 348 KB Output is correct
18 Correct 1 ms 604 KB Output is correct
19 Correct 1 ms 604 KB Output is correct
20 Correct 1 ms 604 KB Output is correct
21 Correct 1 ms 600 KB Output is correct
22 Correct 1 ms 600 KB Output is correct
23 Correct 1 ms 600 KB Output is correct
24 Correct 1 ms 604 KB Output is correct
25 Correct 272 ms 45480 KB Output is correct
26 Correct 54 ms 24908 KB Output is correct
27 Correct 187 ms 38580 KB Output is correct
28 Correct 210 ms 42956 KB Output is correct
29 Correct 200 ms 39736 KB Output is correct
30 Correct 171 ms 38228 KB Output is correct
31 Correct 260 ms 45076 KB Output is correct
32 Correct 171 ms 39140 KB Output is correct
33 Correct 262 ms 44388 KB Output is correct
34 Correct 1 ms 604 KB Output is correct
35 Correct 1 ms 600 KB Output is correct
36 Correct 1 ms 604 KB Output is correct
37 Correct 1 ms 344 KB Output is correct
38 Correct 1 ms 348 KB Output is correct
39 Correct 1 ms 604 KB Output is correct
40 Correct 1 ms 604 KB Output is correct
41 Correct 1 ms 604 KB Output is correct
42 Correct 2 ms 604 KB Output is correct
43 Correct 1 ms 604 KB Output is correct
44 Correct 1 ms 604 KB Output is correct
45 Correct 1 ms 604 KB Output is correct
46 Correct 1 ms 604 KB Output is correct
47 Correct 1 ms 604 KB Output is correct
48 Correct 1 ms 604 KB Output is correct
49 Correct 1 ms 600 KB Output is correct
50 Correct 2 ms 600 KB Output is correct
51 Correct 1 ms 600 KB Output is correct
52 Correct 1 ms 604 KB Output is correct
53 Correct 1 ms 600 KB Output is correct
54 Correct 1 ms 600 KB Output is correct
55 Correct 1 ms 600 KB Output is correct
56 Correct 1 ms 600 KB Output is correct
57 Correct 1 ms 604 KB Output is correct
58 Correct 257 ms 41852 KB Output is correct
59 Correct 226 ms 44036 KB Output is correct
60 Correct 189 ms 38856 KB Output is correct
61 Correct 239 ms 42432 KB Output is correct
62 Correct 59 ms 25668 KB Output is correct
63 Correct 208 ms 42208 KB Output is correct
64 Correct 196 ms 39324 KB Output is correct
65 Correct 226 ms 43232 KB Output is correct
66 Correct 288 ms 44984 KB Output is correct
67 Correct 184 ms 37712 KB Output is correct
68 Correct 245 ms 43468 KB Output is correct
69 Correct 241 ms 42236 KB Output is correct
70 Correct 161 ms 37268 KB Output is correct
71 Correct 238 ms 39472 KB Output is correct
72 Correct 176 ms 38736 KB Output is correct
73 Correct 235 ms 45336 KB Output is correct
74 Correct 182 ms 38268 KB Output is correct
75 Correct 238 ms 44008 KB Output is correct
76 Correct 228 ms 44624 KB Output is correct
77 Correct 228 ms 43452 KB Output is correct
78 Correct 178 ms 38264 KB Output is correct
79 Correct 269 ms 43240 KB Output is correct
80 Correct 216 ms 39484 KB Output is correct
81 Correct 239 ms 43716 KB Output is correct