답안 #933690

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
933690	2024-02-26T05:34:50 Z	oblantis	Network (BOI15_net)	C++17	100 / 100	376 ms	81232 KB

#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
#define all(v) v.begin(), v.end()
#define pb push_back
#define ss second
#define ff first
#define vt vector
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int inf = 1e9;
const int mod = 1e9+7;
const int maxn = 5e5 + 1;

vt<pii> ans;
vt<int> g[maxn];
pii dfs(int v, int p){
	int pr = -1, rp = -1;
	if(g[v].size() == 1)pr = v;
	for(auto i : g[v]){
		if(i == p)continue;
		pii wt = dfs(i, v);
		if(pr == -1)pr = wt.ff;
		else if(wt.ff != -1){
			if(rp == -1)rp = wt.ff;
			else {
				ans.pb({rp, wt.ff});
				rp = -1;
			}
		}
		if(wt.ss != -1){
			if(rp == -1)rp = wt.ss;
			else {
				ans.pb({pr, wt.ss});
				pr = rp;
				rp = -1;
			}
		}
	}
	return {pr, rp};
}
void solve() {
	int n;
	cin >> n;
	for(int i = 0, u, v; i < n - 1; i++){
		cin >> u >> v;
		g[u].pb(v), g[v].pb(u);
	}
	int t = 1;
	for(int i = 1; i <= n; i++)if((int)g[i].size() > 1)t = i;
	pii wt = dfs(t, 0);
	if(wt.ss != -1)ans.pb({wt.ff, wt.ss});
	else ans.pb({wt.ff, t});
	cout << ans.size() << '\n';
	for(auto i : ans)cout << i.ff << ' ' << i.ss << '\n';
}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int times = 1;
	//cin >> times;
	for(int i = 1; i <= times; i++) {
		solve();
	}
	return 0;
}

Subtask #1
18.0 / 18.0

#	결과	실행 시간	메모리	Grader output
1	Correct	4 ms	12124 KB	Output is correct
2	Correct	3 ms	12120 KB	Output is correct
3	Correct	3 ms	12124 KB	Output is correct
4	Correct	4 ms	12124 KB	Output is correct
5	Correct	5 ms	12120 KB	Output is correct
6	Correct	4 ms	12124 KB	Output is correct
7	Correct	4 ms	12124 KB	Output is correct
8	Correct	4 ms	12124 KB	Output is correct
9	Correct	3 ms	12124 KB	Output is correct
10	Correct	4 ms	12124 KB	Output is correct
11	Correct	4 ms	12124 KB	Output is correct
12	Correct	4 ms	12196 KB	Output is correct
13	Correct	4 ms	12124 KB	Output is correct
14	Correct	4 ms	12120 KB	Output is correct
15	Correct	4 ms	12124 KB	Output is correct
16	Correct	4 ms	12132 KB	Output is correct
17	Correct	4 ms	12124 KB	Output is correct
18	Correct	4 ms	12124 KB	Output is correct
19	Correct	4 ms	12120 KB	Output is correct
20	Correct	4 ms	12120 KB	Output is correct

Subtask #2
45.0 / 45.0

#	결과	실행 시간	메모리	Grader output
1	Correct	4 ms	12124 KB	Output is correct
2	Correct	3 ms	12120 KB	Output is correct
3	Correct	3 ms	12124 KB	Output is correct
4	Correct	4 ms	12124 KB	Output is correct
5	Correct	5 ms	12120 KB	Output is correct
6	Correct	4 ms	12124 KB	Output is correct
7	Correct	4 ms	12124 KB	Output is correct
8	Correct	4 ms	12124 KB	Output is correct
9	Correct	3 ms	12124 KB	Output is correct
10	Correct	4 ms	12124 KB	Output is correct
11	Correct	4 ms	12124 KB	Output is correct
12	Correct	4 ms	12196 KB	Output is correct
13	Correct	4 ms	12124 KB	Output is correct
14	Correct	4 ms	12120 KB	Output is correct
15	Correct	4 ms	12124 KB	Output is correct
16	Correct	4 ms	12132 KB	Output is correct
17	Correct	4 ms	12124 KB	Output is correct
18	Correct	4 ms	12124 KB	Output is correct
19	Correct	4 ms	12120 KB	Output is correct
20	Correct	4 ms	12120 KB	Output is correct
21	Correct	4 ms	12200 KB	Output is correct
22	Correct	4 ms	12124 KB	Output is correct
23	Correct	5 ms	12124 KB	Output is correct
24	Correct	4 ms	12124 KB	Output is correct
25	Correct	5 ms	12124 KB	Output is correct
26	Correct	4 ms	12124 KB	Output is correct
27	Correct	4 ms	12148 KB	Output is correct
28	Correct	5 ms	12124 KB	Output is correct
29	Correct	5 ms	12216 KB	Output is correct
30	Correct	5 ms	12124 KB	Output is correct
31	Correct	4 ms	12124 KB	Output is correct
32	Correct	5 ms	12124 KB	Output is correct
33	Correct	4 ms	12144 KB	Output is correct
34	Correct	4 ms	12124 KB	Output is correct
35	Correct	4 ms	12124 KB	Output is correct
36	Correct	4 ms	12124 KB	Output is correct
37	Correct	4 ms	12120 KB	Output is correct
38	Correct	4 ms	12120 KB	Output is correct
39	Correct	4 ms	12120 KB	Output is correct
40	Correct	4 ms	12120 KB	Output is correct
41	Correct	4 ms	12120 KB	Output is correct
42	Correct	4 ms	12120 KB	Output is correct
43	Correct	4 ms	12200 KB	Output is correct
44	Correct	5 ms	12128 KB	Output is correct
45	Correct	4 ms	12124 KB	Output is correct
46	Correct	5 ms	12380 KB	Output is correct
47	Correct	4 ms	12124 KB	Output is correct
48	Correct	4 ms	12124 KB	Output is correct
49	Correct	4 ms	12124 KB	Output is correct
50	Correct	5 ms	12124 KB	Output is correct
51	Correct	4 ms	12124 KB	Output is correct
52	Correct	4 ms	12124 KB	Output is correct
53	Correct	4 ms	12124 KB	Output is correct
54	Correct	4 ms	12200 KB	Output is correct
55	Correct	4 ms	12124 KB	Output is correct
56	Correct	4 ms	12208 KB	Output is correct
57	Correct	5 ms	12120 KB	Output is correct
58	Correct	4 ms	12124 KB	Output is correct

Subtask #3
37.0 / 37.0

#	결과	실행 시간	메모리	Grader output
1	Correct	4 ms	12124 KB	Output is correct
2	Correct	3 ms	12120 KB	Output is correct
3	Correct	3 ms	12124 KB	Output is correct
4	Correct	4 ms	12124 KB	Output is correct
5	Correct	5 ms	12120 KB	Output is correct
6	Correct	4 ms	12124 KB	Output is correct
7	Correct	4 ms	12124 KB	Output is correct
8	Correct	4 ms	12124 KB	Output is correct
9	Correct	3 ms	12124 KB	Output is correct
10	Correct	4 ms	12124 KB	Output is correct
11	Correct	4 ms	12124 KB	Output is correct
12	Correct	4 ms	12196 KB	Output is correct
13	Correct	4 ms	12124 KB	Output is correct
14	Correct	4 ms	12120 KB	Output is correct
15	Correct	4 ms	12124 KB	Output is correct
16	Correct	4 ms	12132 KB	Output is correct
17	Correct	4 ms	12124 KB	Output is correct
18	Correct	4 ms	12124 KB	Output is correct
19	Correct	4 ms	12120 KB	Output is correct
20	Correct	4 ms	12120 KB	Output is correct
21	Correct	4 ms	12200 KB	Output is correct
22	Correct	4 ms	12124 KB	Output is correct
23	Correct	5 ms	12124 KB	Output is correct
24	Correct	4 ms	12124 KB	Output is correct
25	Correct	5 ms	12124 KB	Output is correct
26	Correct	4 ms	12124 KB	Output is correct
27	Correct	4 ms	12148 KB	Output is correct
28	Correct	5 ms	12124 KB	Output is correct
29	Correct	5 ms	12216 KB	Output is correct
30	Correct	5 ms	12124 KB	Output is correct
31	Correct	4 ms	12124 KB	Output is correct
32	Correct	5 ms	12124 KB	Output is correct
33	Correct	4 ms	12144 KB	Output is correct
34	Correct	4 ms	12124 KB	Output is correct
35	Correct	4 ms	12124 KB	Output is correct
36	Correct	4 ms	12124 KB	Output is correct
37	Correct	4 ms	12120 KB	Output is correct
38	Correct	4 ms	12120 KB	Output is correct
39	Correct	4 ms	12120 KB	Output is correct
40	Correct	4 ms	12120 KB	Output is correct
41	Correct	4 ms	12120 KB	Output is correct
42	Correct	4 ms	12120 KB	Output is correct
43	Correct	4 ms	12200 KB	Output is correct
44	Correct	5 ms	12128 KB	Output is correct
45	Correct	4 ms	12124 KB	Output is correct
46	Correct	5 ms	12380 KB	Output is correct
47	Correct	4 ms	12124 KB	Output is correct
48	Correct	4 ms	12124 KB	Output is correct
49	Correct	4 ms	12124 KB	Output is correct
50	Correct	5 ms	12124 KB	Output is correct
51	Correct	4 ms	12124 KB	Output is correct
52	Correct	4 ms	12124 KB	Output is correct
53	Correct	4 ms	12124 KB	Output is correct
54	Correct	4 ms	12200 KB	Output is correct
55	Correct	4 ms	12124 KB	Output is correct
56	Correct	4 ms	12208 KB	Output is correct
57	Correct	5 ms	12120 KB	Output is correct
58	Correct	4 ms	12124 KB	Output is correct
59	Correct	226 ms	36068 KB	Output is correct
60	Correct	292 ms	39156 KB	Output is correct
61	Correct	4 ms	12124 KB	Output is correct
62	Correct	4 ms	12124 KB	Output is correct
63	Correct	227 ms	33604 KB	Output is correct
64	Correct	5 ms	12632 KB	Output is correct
65	Correct	11 ms	14428 KB	Output is correct
66	Correct	71 ms	30396 KB	Output is correct
67	Correct	376 ms	81232 KB	Output is correct
68	Correct	348 ms	66408 KB	Output is correct
69	Correct	7 ms	12892 KB	Output is correct
70	Correct	49 ms	21320 KB	Output is correct
71	Correct	188 ms	41792 KB	Output is correct
72	Correct	182 ms	40772 KB	Output is correct
73	Correct	45 ms	19152 KB	Output is correct
74	Correct	350 ms	37624 KB	Output is correct
75	Correct	17 ms	15320 KB	Output is correct
76	Correct	178 ms	41700 KB	Output is correct
77	Correct	221 ms	41628 KB	Output is correct
78	Correct	24 ms	16232 KB	Output is correct
79	Correct	314 ms	55836 KB	Output is correct
80	Correct	5 ms	12376 KB	Output is correct
81	Correct	52 ms	21388 KB	Output is correct
82	Correct	226 ms	39492 KB	Output is correct
83	Correct	295 ms	37732 KB	Output is correct
84	Correct	273 ms	37932 KB	Output is correct
85	Correct	273 ms	37828 KB	Output is correct
86	Correct	274 ms	38852 KB	Output is correct
87	Correct	290 ms	38832 KB	Output is correct

답안 #933690

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