Submission #104668

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
104668	2019-04-08T16:04:27 Z	Anai	Network (BOI15_net)	C++14	100 / 100	963 ms	69472 KB

#include <bits/stdc++.h>
#define x first
#define y second
using namespace std;

using pii = pair<int, int>;

const int N = 5e5 + 5;


vector<int> g[N], lvs[N];
bool matched[N];

vector<pii> ant;
int n, root;


static void dfs(int u) {
	if (g[u].empty())
		lvs[u].push_back(u);

	int total = 0;

	for (auto v: g[u]) {
		g[v].erase(remove(begin(g[v]), end(g[v]), u), end(g[v]));
		dfs(v);
		total+= lvs[v].size(); }

	sort(begin(g[u]), end(g[u]), [&](const int &a, const int &b) {
		return lvs[a].size() > lvs[b].size(); });
	if (g[u].size() == 1)
		swap(lvs[g[u][0]], lvs[u]);

	for (auto v: g[u]) {
		while (lvs[u].size() && lvs[v].size() && total > (u == root ? 0 : 2)) {
			ant.emplace_back(lvs[u].back(), lvs[v].back());
			lvs[u].pop_back();
			lvs[v].pop_back();
			total-= 2; }
		while (lvs[v].size()) {
			lvs[u].push_back(lvs[v].back());
			lvs[v].pop_back(); } } }

int main() {
#ifdef HOME
	freopen("network.in", "r", stdin);
	freopen("network.out", "w", stdout);
#endif
	ios::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);

	cin >> n;
	for (int u, v, i = 1; i < n; ++i) {
		cin >> u >> v;
		g[u].push_back(v);
		g[v].push_back(u); }

	for (root = 1; g[root].size() == 1; ++root);
	dfs(root);

	if (lvs[root].size())
		ant.emplace_back(root, lvs[root][0]);

	cout << ant.size() << '\n';
	for (auto i: ant)
		cout << i.x << ' ' << i.y << '\n';

	return 0; }

Subtask #1
18.0 / 18.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	24 ms	23808 KB	Output is correct
2	Correct	23 ms	23808 KB	Output is correct
3	Correct	26 ms	23808 KB	Output is correct
4	Correct	29 ms	23808 KB	Output is correct
5	Correct	27 ms	23808 KB	Output is correct
6	Correct	29 ms	23808 KB	Output is correct
7	Correct	28 ms	23936 KB	Output is correct
8	Correct	26 ms	23800 KB	Output is correct
9	Correct	25 ms	23804 KB	Output is correct
10	Correct	26 ms	23800 KB	Output is correct
11	Correct	28 ms	23808 KB	Output is correct
12	Correct	31 ms	23808 KB	Output is correct
13	Correct	27 ms	23808 KB	Output is correct
14	Correct	26 ms	23808 KB	Output is correct
15	Correct	26 ms	23896 KB	Output is correct
16	Correct	30 ms	23808 KB	Output is correct
17	Correct	31 ms	23800 KB	Output is correct
18	Correct	30 ms	23856 KB	Output is correct
19	Correct	30 ms	23808 KB	Output is correct
20	Correct	28 ms	23808 KB	Output is correct

Subtask #2
45.0 / 45.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	24 ms	23808 KB	Output is correct
2	Correct	23 ms	23808 KB	Output is correct
3	Correct	26 ms	23808 KB	Output is correct
4	Correct	29 ms	23808 KB	Output is correct
5	Correct	27 ms	23808 KB	Output is correct
6	Correct	29 ms	23808 KB	Output is correct
7	Correct	28 ms	23936 KB	Output is correct
8	Correct	26 ms	23800 KB	Output is correct
9	Correct	25 ms	23804 KB	Output is correct
10	Correct	26 ms	23800 KB	Output is correct
11	Correct	28 ms	23808 KB	Output is correct
12	Correct	31 ms	23808 KB	Output is correct
13	Correct	27 ms	23808 KB	Output is correct
14	Correct	26 ms	23808 KB	Output is correct
15	Correct	26 ms	23896 KB	Output is correct
16	Correct	30 ms	23808 KB	Output is correct
17	Correct	31 ms	23800 KB	Output is correct
18	Correct	30 ms	23856 KB	Output is correct
19	Correct	30 ms	23808 KB	Output is correct
20	Correct	28 ms	23808 KB	Output is correct
21	Correct	30 ms	23800 KB	Output is correct
22	Correct	26 ms	24056 KB	Output is correct
23	Correct	34 ms	24056 KB	Output is correct
24	Correct	31 ms	24184 KB	Output is correct
25	Correct	27 ms	23928 KB	Output is correct
26	Correct	32 ms	23936 KB	Output is correct
27	Correct	31 ms	24056 KB	Output is correct
28	Correct	31 ms	23936 KB	Output is correct
29	Correct	26 ms	23928 KB	Output is correct
30	Correct	26 ms	23928 KB	Output is correct
31	Correct	27 ms	23936 KB	Output is correct
32	Correct	25 ms	23808 KB	Output is correct
33	Correct	26 ms	23808 KB	Output is correct
34	Correct	24 ms	23808 KB	Output is correct
35	Correct	26 ms	23808 KB	Output is correct
36	Correct	26 ms	23808 KB	Output is correct
37	Correct	29 ms	23936 KB	Output is correct
38	Correct	31 ms	23936 KB	Output is correct
39	Correct	27 ms	23808 KB	Output is correct
40	Correct	31 ms	23808 KB	Output is correct
41	Correct	25 ms	23936 KB	Output is correct
42	Correct	24 ms	23808 KB	Output is correct
43	Correct	27 ms	23928 KB	Output is correct
44	Correct	30 ms	23800 KB	Output is correct
45	Correct	25 ms	23808 KB	Output is correct
46	Correct	26 ms	23936 KB	Output is correct
47	Correct	25 ms	23808 KB	Output is correct
48	Correct	30 ms	23800 KB	Output is correct
49	Correct	28 ms	23928 KB	Output is correct
50	Correct	26 ms	23808 KB	Output is correct
51	Correct	29 ms	23800 KB	Output is correct
52	Correct	30 ms	23928 KB	Output is correct
53	Correct	31 ms	23920 KB	Output is correct
54	Correct	27 ms	23808 KB	Output is correct
55	Correct	26 ms	23908 KB	Output is correct
56	Correct	26 ms	23936 KB	Output is correct
57	Correct	28 ms	23908 KB	Output is correct
58	Correct	29 ms	24044 KB	Output is correct

Subtask #3
37.0 / 37.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	24 ms	23808 KB	Output is correct
2	Correct	23 ms	23808 KB	Output is correct
3	Correct	26 ms	23808 KB	Output is correct
4	Correct	29 ms	23808 KB	Output is correct
5	Correct	27 ms	23808 KB	Output is correct
6	Correct	29 ms	23808 KB	Output is correct
7	Correct	28 ms	23936 KB	Output is correct
8	Correct	26 ms	23800 KB	Output is correct
9	Correct	25 ms	23804 KB	Output is correct
10	Correct	26 ms	23800 KB	Output is correct
11	Correct	28 ms	23808 KB	Output is correct
12	Correct	31 ms	23808 KB	Output is correct
13	Correct	27 ms	23808 KB	Output is correct
14	Correct	26 ms	23808 KB	Output is correct
15	Correct	26 ms	23896 KB	Output is correct
16	Correct	30 ms	23808 KB	Output is correct
17	Correct	31 ms	23800 KB	Output is correct
18	Correct	30 ms	23856 KB	Output is correct
19	Correct	30 ms	23808 KB	Output is correct
20	Correct	28 ms	23808 KB	Output is correct
21	Correct	30 ms	23800 KB	Output is correct
22	Correct	26 ms	24056 KB	Output is correct
23	Correct	34 ms	24056 KB	Output is correct
24	Correct	31 ms	24184 KB	Output is correct
25	Correct	27 ms	23928 KB	Output is correct
26	Correct	32 ms	23936 KB	Output is correct
27	Correct	31 ms	24056 KB	Output is correct
28	Correct	31 ms	23936 KB	Output is correct
29	Correct	26 ms	23928 KB	Output is correct
30	Correct	26 ms	23928 KB	Output is correct
31	Correct	27 ms	23936 KB	Output is correct
32	Correct	25 ms	23808 KB	Output is correct
33	Correct	26 ms	23808 KB	Output is correct
34	Correct	24 ms	23808 KB	Output is correct
35	Correct	26 ms	23808 KB	Output is correct
36	Correct	26 ms	23808 KB	Output is correct
37	Correct	29 ms	23936 KB	Output is correct
38	Correct	31 ms	23936 KB	Output is correct
39	Correct	27 ms	23808 KB	Output is correct
40	Correct	31 ms	23808 KB	Output is correct
41	Correct	25 ms	23936 KB	Output is correct
42	Correct	24 ms	23808 KB	Output is correct
43	Correct	27 ms	23928 KB	Output is correct
44	Correct	30 ms	23800 KB	Output is correct
45	Correct	25 ms	23808 KB	Output is correct
46	Correct	26 ms	23936 KB	Output is correct
47	Correct	25 ms	23808 KB	Output is correct
48	Correct	30 ms	23800 KB	Output is correct
49	Correct	28 ms	23928 KB	Output is correct
50	Correct	26 ms	23808 KB	Output is correct
51	Correct	29 ms	23800 KB	Output is correct
52	Correct	30 ms	23928 KB	Output is correct
53	Correct	31 ms	23920 KB	Output is correct
54	Correct	27 ms	23808 KB	Output is correct
55	Correct	26 ms	23908 KB	Output is correct
56	Correct	26 ms	23936 KB	Output is correct
57	Correct	28 ms	23908 KB	Output is correct
58	Correct	29 ms	24044 KB	Output is correct
59	Correct	832 ms	62024 KB	Output is correct
60	Correct	875 ms	66020 KB	Output is correct
61	Correct	25 ms	23808 KB	Output is correct
62	Correct	28 ms	23936 KB	Output is correct
63	Correct	657 ms	57828 KB	Output is correct
64	Correct	27 ms	24320 KB	Output is correct
65	Correct	49 ms	26104 KB	Output is correct
66	Correct	291 ms	42360 KB	Output is correct
67	Correct	890 ms	62968 KB	Output is correct
68	Correct	954 ms	66556 KB	Output is correct
69	Correct	38 ms	25208 KB	Output is correct
70	Correct	228 ms	37608 KB	Output is correct
71	Correct	797 ms	69472 KB	Output is correct
72	Correct	848 ms	66700 KB	Output is correct
73	Correct	226 ms	34032 KB	Output is correct
74	Correct	895 ms	61336 KB	Output is correct
75	Correct	93 ms	28532 KB	Output is correct
76	Correct	834 ms	68304 KB	Output is correct
77	Correct	831 ms	69008 KB	Output is correct
78	Correct	123 ms	28380 KB	Output is correct
79	Correct	963 ms	60792 KB	Output is correct
80	Correct	28 ms	24192 KB	Output is correct
81	Correct	219 ms	37616 KB	Output is correct
82	Correct	862 ms	64892 KB	Output is correct
83	Correct	864 ms	61292 KB	Output is correct
84	Correct	901 ms	61300 KB	Output is correct
85	Correct	875 ms	61228 KB	Output is correct
86	Correct	960 ms	66236 KB	Output is correct
87	Correct	909 ms	66168 KB	Output is correct

Submission #104668

Compilation message

Subtask #1 18.0 / 18.0

Subtask #2 45.0 / 45.0

Subtask #3 37.0 / 37.0

Subtask #1
18.0 / 18.0

Subtask #2
45.0 / 45.0

Subtask #3
37.0 / 37.0