Submission #79567

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
79567	2018-10-15T03:16:44 Z	DrumpfTheGodEmperor	Network (BOI15_net)	C++14	100 / 100	660 ms	41596 KB

#include <bits/stdc++.h>
#define MOD 1000000007
#define INF 1061109567
#define INFLL 4557430888798830399
#define bp __builtin_popcountll
#define pb push_back
#define in(s) freopen(s,"r",stdin);
#define out(s) freopen(s,"w",stdout);
#define fi first
#define se second
#define bw(i,r,l) for (int i=r-1;i>=l;i--)
#define fw(i,l,r) for (int i=l;i<r;i++)
#define fa(i,x) for (auto i:x)
using namespace std;
const int N = 5e5 + 5;
typedef pair<int, int> ii;
int n;
bool used[N];
vector<int> g[N], leafs;
vector<ii> edges;
void dfs(int u, int p) {
	if (g[u].size() == 1) leafs.pb(u);
	fa (v, g[u]) if (v != p) dfs(v, u);
}
signed main() {
	#ifdef BLU
	in("blu.inp");
	#endif
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	cin >> n;
	fw (i, 1, n) {
		int u, v;
		cin >> u >> v;
		u--, v--;
		g[u].pb(v), g[v].pb(u);
	}
	int root = -1;
	fw (i, 0, n) if (g[i].size() > 1) {
		root = i;
		break;
	}
	dfs(root, -1);
	int tmp = leafs.size();
	cout << (tmp + 1) / 2 << "\n";
	if (tmp & 1) {
		cout << root + 1 << " " << leafs[tmp / 2] + 1 << "\n";
		fw (i, 0, tmp / 2) cout << leafs[i] + 1 << " " << leafs[i + tmp / 2 + 1] + 1 << "\n";
	} else {
		fw (i, 0, tmp / 2) cout << leafs[i] + 1 << " " << leafs[i + tmp / 2] + 1 << "\n";
	}
	return 0;
}

Subtask #1
18.0 / 18.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	15 ms	12152 KB	Output is correct
2	Correct	12 ms	12284 KB	Output is correct
3	Correct	12 ms	12284 KB	Output is correct
4	Correct	13 ms	12324 KB	Output is correct
5	Correct	12 ms	12324 KB	Output is correct
6	Correct	12 ms	12324 KB	Output is correct
7	Correct	12 ms	12324 KB	Output is correct
8	Correct	12 ms	12324 KB	Output is correct
9	Correct	13 ms	12324 KB	Output is correct
10	Correct	13 ms	12324 KB	Output is correct
11	Correct	12 ms	12324 KB	Output is correct
12	Correct	13 ms	12324 KB	Output is correct
13	Correct	12 ms	12324 KB	Output is correct
14	Correct	12 ms	12324 KB	Output is correct
15	Correct	11 ms	12324 KB	Output is correct
16	Correct	13 ms	12324 KB	Output is correct
17	Correct	12 ms	12392 KB	Output is correct
18	Correct	12 ms	12392 KB	Output is correct
19	Correct	13 ms	12392 KB	Output is correct
20	Correct	12 ms	12392 KB	Output is correct

Subtask #2
45.0 / 45.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	15 ms	12152 KB	Output is correct
2	Correct	12 ms	12284 KB	Output is correct
3	Correct	12 ms	12284 KB	Output is correct
4	Correct	13 ms	12324 KB	Output is correct
5	Correct	12 ms	12324 KB	Output is correct
6	Correct	12 ms	12324 KB	Output is correct
7	Correct	12 ms	12324 KB	Output is correct
8	Correct	12 ms	12324 KB	Output is correct
9	Correct	13 ms	12324 KB	Output is correct
10	Correct	13 ms	12324 KB	Output is correct
11	Correct	12 ms	12324 KB	Output is correct
12	Correct	13 ms	12324 KB	Output is correct
13	Correct	12 ms	12324 KB	Output is correct
14	Correct	12 ms	12324 KB	Output is correct
15	Correct	11 ms	12324 KB	Output is correct
16	Correct	13 ms	12324 KB	Output is correct
17	Correct	12 ms	12392 KB	Output is correct
18	Correct	12 ms	12392 KB	Output is correct
19	Correct	13 ms	12392 KB	Output is correct
20	Correct	12 ms	12392 KB	Output is correct
21	Correct	12 ms	12392 KB	Output is correct
22	Correct	13 ms	12392 KB	Output is correct
23	Correct	14 ms	12428 KB	Output is correct
24	Correct	13 ms	12428 KB	Output is correct
25	Correct	13 ms	12428 KB	Output is correct
26	Correct	13 ms	12428 KB	Output is correct
27	Correct	12 ms	12428 KB	Output is correct
28	Correct	14 ms	12444 KB	Output is correct
29	Correct	13 ms	12444 KB	Output is correct
30	Correct	12 ms	12444 KB	Output is correct
31	Correct	13 ms	12444 KB	Output is correct
32	Correct	13 ms	12444 KB	Output is correct
33	Correct	12 ms	12444 KB	Output is correct
34	Correct	13 ms	12444 KB	Output is correct
35	Correct	13 ms	12460 KB	Output is correct
36	Correct	12 ms	12460 KB	Output is correct
37	Correct	13 ms	12460 KB	Output is correct
38	Correct	13 ms	12504 KB	Output is correct
39	Correct	13 ms	12504 KB	Output is correct
40	Correct	16 ms	12504 KB	Output is correct
41	Correct	13 ms	12504 KB	Output is correct
42	Correct	12 ms	12504 KB	Output is correct
43	Correct	13 ms	12504 KB	Output is correct
44	Correct	12 ms	12504 KB	Output is correct
45	Correct	13 ms	12504 KB	Output is correct
46	Correct	13 ms	12504 KB	Output is correct
47	Correct	12 ms	12504 KB	Output is correct
48	Correct	12 ms	12504 KB	Output is correct
49	Correct	13 ms	12504 KB	Output is correct
50	Correct	13 ms	12504 KB	Output is correct
51	Correct	12 ms	12504 KB	Output is correct
52	Correct	12 ms	12504 KB	Output is correct
53	Correct	13 ms	12604 KB	Output is correct
54	Correct	12 ms	12604 KB	Output is correct
55	Correct	12 ms	12604 KB	Output is correct
56	Correct	12 ms	12604 KB	Output is correct
57	Correct	13 ms	12604 KB	Output is correct
58	Correct	13 ms	12604 KB	Output is correct

Subtask #3
37.0 / 37.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	15 ms	12152 KB	Output is correct
2	Correct	12 ms	12284 KB	Output is correct
3	Correct	12 ms	12284 KB	Output is correct
4	Correct	13 ms	12324 KB	Output is correct
5	Correct	12 ms	12324 KB	Output is correct
6	Correct	12 ms	12324 KB	Output is correct
7	Correct	12 ms	12324 KB	Output is correct
8	Correct	12 ms	12324 KB	Output is correct
9	Correct	13 ms	12324 KB	Output is correct
10	Correct	13 ms	12324 KB	Output is correct
11	Correct	12 ms	12324 KB	Output is correct
12	Correct	13 ms	12324 KB	Output is correct
13	Correct	12 ms	12324 KB	Output is correct
14	Correct	12 ms	12324 KB	Output is correct
15	Correct	11 ms	12324 KB	Output is correct
16	Correct	13 ms	12324 KB	Output is correct
17	Correct	12 ms	12392 KB	Output is correct
18	Correct	12 ms	12392 KB	Output is correct
19	Correct	13 ms	12392 KB	Output is correct
20	Correct	12 ms	12392 KB	Output is correct
21	Correct	12 ms	12392 KB	Output is correct
22	Correct	13 ms	12392 KB	Output is correct
23	Correct	14 ms	12428 KB	Output is correct
24	Correct	13 ms	12428 KB	Output is correct
25	Correct	13 ms	12428 KB	Output is correct
26	Correct	13 ms	12428 KB	Output is correct
27	Correct	12 ms	12428 KB	Output is correct
28	Correct	14 ms	12444 KB	Output is correct
29	Correct	13 ms	12444 KB	Output is correct
30	Correct	12 ms	12444 KB	Output is correct
31	Correct	13 ms	12444 KB	Output is correct
32	Correct	13 ms	12444 KB	Output is correct
33	Correct	12 ms	12444 KB	Output is correct
34	Correct	13 ms	12444 KB	Output is correct
35	Correct	13 ms	12460 KB	Output is correct
36	Correct	12 ms	12460 KB	Output is correct
37	Correct	13 ms	12460 KB	Output is correct
38	Correct	13 ms	12504 KB	Output is correct
39	Correct	13 ms	12504 KB	Output is correct
40	Correct	16 ms	12504 KB	Output is correct
41	Correct	13 ms	12504 KB	Output is correct
42	Correct	12 ms	12504 KB	Output is correct
43	Correct	13 ms	12504 KB	Output is correct
44	Correct	12 ms	12504 KB	Output is correct
45	Correct	13 ms	12504 KB	Output is correct
46	Correct	13 ms	12504 KB	Output is correct
47	Correct	12 ms	12504 KB	Output is correct
48	Correct	12 ms	12504 KB	Output is correct
49	Correct	13 ms	12504 KB	Output is correct
50	Correct	13 ms	12504 KB	Output is correct
51	Correct	12 ms	12504 KB	Output is correct
52	Correct	12 ms	12504 KB	Output is correct
53	Correct	13 ms	12604 KB	Output is correct
54	Correct	12 ms	12604 KB	Output is correct
55	Correct	12 ms	12604 KB	Output is correct
56	Correct	12 ms	12604 KB	Output is correct
57	Correct	13 ms	12604 KB	Output is correct
58	Correct	13 ms	12604 KB	Output is correct
59	Correct	445 ms	30400 KB	Output is correct
60	Correct	530 ms	32616 KB	Output is correct
61	Correct	13 ms	32616 KB	Output is correct
62	Correct	12 ms	32616 KB	Output is correct
63	Correct	380 ms	32616 KB	Output is correct
64	Correct	16 ms	32616 KB	Output is correct
65	Correct	36 ms	32616 KB	Output is correct
66	Correct	186 ms	32616 KB	Output is correct
67	Correct	617 ms	40632 KB	Output is correct
68	Correct	641 ms	41596 KB	Output is correct
69	Correct	20 ms	41596 KB	Output is correct
70	Correct	106 ms	41596 KB	Output is correct
71	Correct	398 ms	41596 KB	Output is correct
72	Correct	382 ms	41596 KB	Output is correct
73	Correct	146 ms	41596 KB	Output is correct
74	Correct	541 ms	41596 KB	Output is correct
75	Correct	41 ms	41596 KB	Output is correct
76	Correct	376 ms	41596 KB	Output is correct
77	Correct	373 ms	41596 KB	Output is correct
78	Correct	41 ms	41596 KB	Output is correct
79	Correct	660 ms	41596 KB	Output is correct
80	Correct	14 ms	41596 KB	Output is correct
81	Correct	130 ms	41596 KB	Output is correct
82	Correct	495 ms	41596 KB	Output is correct
83	Correct	531 ms	41596 KB	Output is correct
84	Correct	531 ms	41596 KB	Output is correct
85	Correct	504 ms	41596 KB	Output is correct
86	Correct	517 ms	41596 KB	Output is correct
87	Correct	498 ms	41596 KB	Output is correct

Submission #79567

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