Submission #107936

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
107936	2019-04-26T09:34:04 Z	shash42	Network (BOI15_net)	C++11	100 / 100	971 ms	73160 KB

#include<bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define pii pair<int, int>

using namespace std;

const int N=5e5+5;
int n, tmr=0;
vector<int> adj[N], lvlst[N];
vector< pii > ans;
int lv[N], p[N];

struct lvsrt
{
	bool operator()(const int &a, const int &b)
	{
		return lv[a]>lv[b];
	}	
};
void dfs(int u)
{
	for(auto &v: adj[u])
	{
		if(v!=p[u])
		{
			p[v]=u;
			dfs(v);
			lv[u]+=lv[v];
		}
	}
	if(adj[u].size()==1 && u!=1)
	{
		tmr++;
		lv[u]=1;
	}
}
int findg(int u)
{
	//cout << tmr << " finding g: " << u << endl;
	for(auto &v: adj[u])
	{
		if(lv[v]>tmr/2 && p[u]!=v)
		{
			return findg(v);
		}
	}
	return u;
}
void findlvs(int u, int subt)
{
	for(auto &v: adj[u])
	{
		if(v!=p[u])
		{
			p[v]=u;
			findlvs(v, subt);
		}
	}
	if(adj[u].size()==1)
	{
		lvlst[subt].pb(u);
	}
}
int main()
{
	ios_base::sync_with_stdio(false); cin.tie(0);
	cin >> n;
	for(int i = 1; i < n; i++)
	{
		int u, v;
		cin >> u >> v;
		adj[u].pb(v);
		adj[v].pb(u);
	}
	p[1]=1;	
	dfs(1);
	if(adj[1].size()==1) tmr++;
	int g=findg(1);
//	cout << g;
	sort(adj[g].begin(), adj[g].end(), lvsrt());
	memset(p, 0, n+1);
	int numsubt=adj[g].size();
	for(int i = 0; i < numsubt; i++)
	{
		p[adj[g][i]]=g;
		findlvs(adj[g][i], i);
	}
	int itr=0;
	for(int i = 0; i < tmr/2; i++) ans.pb(mp(0, 0));
	bool chk=false;
	for(int i = 0; i < numsubt; i++)
	{
		for(auto &v: lvlst[i])
		{
			if(!chk && itr==tmr/2)
			{
				itr=0;
				chk=true;
			}
			if(!chk) ans[itr].first=v;
			else ans[itr].second=v;
			if(chk && itr==tmr/2) break;
			itr++;
		}
	}
	if(tmr%2)
	{
		ans.pb(mp(g, lvlst[numsubt-1].back()));
	}
	cout << ans.size() << "\n";
	for(auto &v: ans)
	{
		cout << v.first << " " << v.second << "\n";
	}
}

Subtask #1
18.0 / 18.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	34 ms	23808 KB	Output is correct
2	Correct	30 ms	23800 KB	Output is correct
3	Correct	25 ms	23808 KB	Output is correct
4	Correct	23 ms	23808 KB	Output is correct
5	Correct	24 ms	23808 KB	Output is correct
6	Correct	25 ms	23780 KB	Output is correct
7	Correct	23 ms	23808 KB	Output is correct
8	Correct	33 ms	23808 KB	Output is correct
9	Correct	25 ms	23808 KB	Output is correct
10	Correct	25 ms	23800 KB	Output is correct
11	Correct	25 ms	23808 KB	Output is correct
12	Correct	25 ms	23808 KB	Output is correct
13	Correct	25 ms	23908 KB	Output is correct
14	Correct	24 ms	23808 KB	Output is correct
15	Correct	26 ms	23800 KB	Output is correct
16	Correct	26 ms	23800 KB	Output is correct
17	Correct	28 ms	23812 KB	Output is correct
18	Correct	28 ms	23808 KB	Output is correct
19	Correct	25 ms	23808 KB	Output is correct
20	Correct	25 ms	23800 KB	Output is correct

Subtask #2
45.0 / 45.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	34 ms	23808 KB	Output is correct
2	Correct	30 ms	23800 KB	Output is correct
3	Correct	25 ms	23808 KB	Output is correct
4	Correct	23 ms	23808 KB	Output is correct
5	Correct	24 ms	23808 KB	Output is correct
6	Correct	25 ms	23780 KB	Output is correct
7	Correct	23 ms	23808 KB	Output is correct
8	Correct	33 ms	23808 KB	Output is correct
9	Correct	25 ms	23808 KB	Output is correct
10	Correct	25 ms	23800 KB	Output is correct
11	Correct	25 ms	23808 KB	Output is correct
12	Correct	25 ms	23808 KB	Output is correct
13	Correct	25 ms	23908 KB	Output is correct
14	Correct	24 ms	23808 KB	Output is correct
15	Correct	26 ms	23800 KB	Output is correct
16	Correct	26 ms	23800 KB	Output is correct
17	Correct	28 ms	23812 KB	Output is correct
18	Correct	28 ms	23808 KB	Output is correct
19	Correct	25 ms	23808 KB	Output is correct
20	Correct	25 ms	23800 KB	Output is correct
21	Correct	25 ms	23808 KB	Output is correct
22	Correct	26 ms	24064 KB	Output is correct
23	Correct	25 ms	23936 KB	Output is correct
24	Correct	24 ms	24092 KB	Output is correct
25	Correct	26 ms	23908 KB	Output is correct
26	Correct	29 ms	23936 KB	Output is correct
27	Correct	25 ms	23936 KB	Output is correct
28	Correct	24 ms	23936 KB	Output is correct
29	Correct	25 ms	23976 KB	Output is correct
30	Correct	24 ms	23800 KB	Output is correct
31	Correct	27 ms	24056 KB	Output is correct
32	Correct	26 ms	23808 KB	Output is correct
33	Correct	24 ms	23808 KB	Output is correct
34	Correct	29 ms	23872 KB	Output is correct
35	Correct	27 ms	23808 KB	Output is correct
36	Correct	28 ms	23808 KB	Output is correct
37	Correct	26 ms	23936 KB	Output is correct
38	Correct	27 ms	23908 KB	Output is correct
39	Correct	27 ms	23808 KB	Output is correct
40	Correct	23 ms	23808 KB	Output is correct
41	Correct	24 ms	23772 KB	Output is correct
42	Correct	29 ms	23928 KB	Output is correct
43	Correct	27 ms	23936 KB	Output is correct
44	Correct	24 ms	23936 KB	Output is correct
45	Correct	26 ms	23928 KB	Output is correct
46	Correct	24 ms	23928 KB	Output is correct
47	Correct	34 ms	23848 KB	Output is correct
48	Correct	31 ms	23800 KB	Output is correct
49	Correct	25 ms	23928 KB	Output is correct
50	Correct	25 ms	23808 KB	Output is correct
51	Correct	25 ms	23808 KB	Output is correct
52	Correct	25 ms	23808 KB	Output is correct
53	Correct	25 ms	23936 KB	Output is correct
54	Correct	34 ms	23912 KB	Output is correct
55	Correct	23 ms	23808 KB	Output is correct
56	Correct	24 ms	23868 KB	Output is correct
57	Correct	24 ms	23800 KB	Output is correct
58	Correct	24 ms	23928 KB	Output is correct

Subtask #3
37.0 / 37.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	34 ms	23808 KB	Output is correct
2	Correct	30 ms	23800 KB	Output is correct
3	Correct	25 ms	23808 KB	Output is correct
4	Correct	23 ms	23808 KB	Output is correct
5	Correct	24 ms	23808 KB	Output is correct
6	Correct	25 ms	23780 KB	Output is correct
7	Correct	23 ms	23808 KB	Output is correct
8	Correct	33 ms	23808 KB	Output is correct
9	Correct	25 ms	23808 KB	Output is correct
10	Correct	25 ms	23800 KB	Output is correct
11	Correct	25 ms	23808 KB	Output is correct
12	Correct	25 ms	23808 KB	Output is correct
13	Correct	25 ms	23908 KB	Output is correct
14	Correct	24 ms	23808 KB	Output is correct
15	Correct	26 ms	23800 KB	Output is correct
16	Correct	26 ms	23800 KB	Output is correct
17	Correct	28 ms	23812 KB	Output is correct
18	Correct	28 ms	23808 KB	Output is correct
19	Correct	25 ms	23808 KB	Output is correct
20	Correct	25 ms	23800 KB	Output is correct
21	Correct	25 ms	23808 KB	Output is correct
22	Correct	26 ms	24064 KB	Output is correct
23	Correct	25 ms	23936 KB	Output is correct
24	Correct	24 ms	24092 KB	Output is correct
25	Correct	26 ms	23908 KB	Output is correct
26	Correct	29 ms	23936 KB	Output is correct
27	Correct	25 ms	23936 KB	Output is correct
28	Correct	24 ms	23936 KB	Output is correct
29	Correct	25 ms	23976 KB	Output is correct
30	Correct	24 ms	23800 KB	Output is correct
31	Correct	27 ms	24056 KB	Output is correct
32	Correct	26 ms	23808 KB	Output is correct
33	Correct	24 ms	23808 KB	Output is correct
34	Correct	29 ms	23872 KB	Output is correct
35	Correct	27 ms	23808 KB	Output is correct
36	Correct	28 ms	23808 KB	Output is correct
37	Correct	26 ms	23936 KB	Output is correct
38	Correct	27 ms	23908 KB	Output is correct
39	Correct	27 ms	23808 KB	Output is correct
40	Correct	23 ms	23808 KB	Output is correct
41	Correct	24 ms	23772 KB	Output is correct
42	Correct	29 ms	23928 KB	Output is correct
43	Correct	27 ms	23936 KB	Output is correct
44	Correct	24 ms	23936 KB	Output is correct
45	Correct	26 ms	23928 KB	Output is correct
46	Correct	24 ms	23928 KB	Output is correct
47	Correct	34 ms	23848 KB	Output is correct
48	Correct	31 ms	23800 KB	Output is correct
49	Correct	25 ms	23928 KB	Output is correct
50	Correct	25 ms	23808 KB	Output is correct
51	Correct	25 ms	23808 KB	Output is correct
52	Correct	25 ms	23808 KB	Output is correct
53	Correct	25 ms	23936 KB	Output is correct
54	Correct	34 ms	23912 KB	Output is correct
55	Correct	23 ms	23808 KB	Output is correct
56	Correct	24 ms	23868 KB	Output is correct
57	Correct	24 ms	23800 KB	Output is correct
58	Correct	24 ms	23928 KB	Output is correct
59	Correct	639 ms	56216 KB	Output is correct
60	Correct	819 ms	55844 KB	Output is correct
61	Correct	26 ms	23808 KB	Output is correct
62	Correct	25 ms	23808 KB	Output is correct
63	Correct	594 ms	51764 KB	Output is correct
64	Correct	32 ms	24312 KB	Output is correct
65	Correct	54 ms	26232 KB	Output is correct
66	Correct	290 ms	44024 KB	Output is correct
67	Correct	868 ms	66880 KB	Output is correct
68	Correct	971 ms	67956 KB	Output is correct
69	Correct	35 ms	25344 KB	Output is correct
70	Correct	191 ms	38712 KB	Output is correct
71	Correct	593 ms	73160 KB	Output is correct
72	Correct	649 ms	70392 KB	Output is correct
73	Correct	184 ms	32296 KB	Output is correct
74	Correct	733 ms	54348 KB	Output is correct
75	Correct	73 ms	28380 KB	Output is correct
76	Correct	615 ms	65724 KB	Output is correct
77	Correct	562 ms	66096 KB	Output is correct
78	Correct	69 ms	28028 KB	Output is correct
79	Correct	916 ms	64608 KB	Output is correct
80	Correct	31 ms	24184 KB	Output is correct
81	Correct	208 ms	37204 KB	Output is correct
82	Correct	750 ms	63584 KB	Output is correct
83	Correct	837 ms	54412 KB	Output is correct
84	Correct	762 ms	54572 KB	Output is correct
85	Correct	789 ms	54956 KB	Output is correct
86	Correct	722 ms	55980 KB	Output is correct
87	Correct	686 ms	55976 KB	Output is correct

Submission #107936

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