답안 #915026

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
915026	2024-01-23T08:10:58 Z	penguin133	Network (BOI15_net)	C++17	100 / 100	673 ms	92880 KB

#include <bits/stdc++.h>
using namespace std;

#define int long long
#define pi pair<int, int>
#define pii pair<int, pi>
#define fi first
#define se second
#ifdef _WIN32
#define getchar_unlocked _getchar_nolock
#endif
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

int n;
vector <int> adj[500005];
vector <int> stuf[500005];
vector <pi> ans;

void dfs(int x, int par){
	bool f = 0;
	for(auto i : adj[x]){
		if(i != par){
			f = 1;
			dfs(i, x);
		}
	}
	if(!f)stuf[x].push_back(x);
	else{
		for(auto i : adj[x]){
			while((int)stuf[x].size() + (int)stuf[i].size() >= 3){
				ans.push_back({stuf[x].back(), stuf[i].back()});
				stuf[x].pop_back(); stuf[i].pop_back();
			}
			for(auto j : stuf[i])stuf[x].push_back(j);
		}
	}
	if(x == 1){
		if((int)adj[x].size() <= 1)stuf[x].push_back(x);
		while(stuf[x].size() >= 2){
			int tmp = stuf[x].back(); stuf[x].pop_back();
			int tmp2 = stuf[x].back(); stuf[x].pop_back();
			ans.push_back({tmp, tmp2});
		}
		if(!stuf[x].empty())ans.push_back({stuf[x].back(), (stuf[x].back() == 1 ? n : 1)});
	}
}

void solve(){
	cin >> n;
	for(int i=1;i<n;i++)
	{
		int a, b; cin >> a >> b;
		adj[a].push_back(b);
		adj[b].push_back(a);
	}
	dfs(1, -1);
	cout << (int)ans.size() << '\n';
	for(auto [i, j] : ans)cout << i << ' ' << j << '\n';
}

main(){
	ios::sync_with_stdio(0);cin.tie(0);
	int tc = 1;
	//cin >> tc;
	for(int tc1=1;tc1<=tc;tc1++){
		// cout << "Case #" << tc1 << ": ";
		solve();
	}
}

Compilation message

net.cpp:61:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   61 | main(){
      | ^~~~

Subtask #1
18.0 / 18.0

#	결과	실행 시간	메모리	Grader output
1	Correct	7 ms	23900 KB	Output is correct
2	Correct	7 ms	23900 KB	Output is correct
3	Correct	7 ms	23896 KB	Output is correct
4	Correct	8 ms	23912 KB	Output is correct
5	Correct	7 ms	23900 KB	Output is correct
6	Correct	7 ms	23896 KB	Output is correct
7	Correct	8 ms	23900 KB	Output is correct
8	Correct	7 ms	23900 KB	Output is correct
9	Correct	7 ms	24152 KB	Output is correct
10	Correct	9 ms	23900 KB	Output is correct
11	Correct	7 ms	23900 KB	Output is correct
12	Correct	7 ms	23900 KB	Output is correct
13	Correct	7 ms	23912 KB	Output is correct
14	Correct	8 ms	23900 KB	Output is correct
15	Correct	7 ms	23900 KB	Output is correct
16	Correct	8 ms	23900 KB	Output is correct
17	Correct	7 ms	23900 KB	Output is correct
18	Correct	7 ms	23900 KB	Output is correct
19	Correct	7 ms	23900 KB	Output is correct
20	Correct	7 ms	23900 KB	Output is correct

Subtask #2
45.0 / 45.0

#	결과	실행 시간	메모리	Grader output
1	Correct	7 ms	23900 KB	Output is correct
2	Correct	7 ms	23900 KB	Output is correct
3	Correct	7 ms	23896 KB	Output is correct
4	Correct	8 ms	23912 KB	Output is correct
5	Correct	7 ms	23900 KB	Output is correct
6	Correct	7 ms	23896 KB	Output is correct
7	Correct	8 ms	23900 KB	Output is correct
8	Correct	7 ms	23900 KB	Output is correct
9	Correct	7 ms	24152 KB	Output is correct
10	Correct	9 ms	23900 KB	Output is correct
11	Correct	7 ms	23900 KB	Output is correct
12	Correct	7 ms	23900 KB	Output is correct
13	Correct	7 ms	23912 KB	Output is correct
14	Correct	8 ms	23900 KB	Output is correct
15	Correct	7 ms	23900 KB	Output is correct
16	Correct	8 ms	23900 KB	Output is correct
17	Correct	7 ms	23900 KB	Output is correct
18	Correct	7 ms	23900 KB	Output is correct
19	Correct	7 ms	23900 KB	Output is correct
20	Correct	7 ms	23900 KB	Output is correct
21	Correct	8 ms	23900 KB	Output is correct
22	Correct	9 ms	23896 KB	Output is correct
23	Correct	8 ms	23900 KB	Output is correct
24	Correct	8 ms	23900 KB	Output is correct
25	Correct	8 ms	23900 KB	Output is correct
26	Correct	8 ms	23900 KB	Output is correct
27	Correct	8 ms	23900 KB	Output is correct
28	Correct	8 ms	23996 KB	Output is correct
29	Correct	7 ms	23900 KB	Output is correct
30	Correct	7 ms	23900 KB	Output is correct
31	Correct	7 ms	23900 KB	Output is correct
32	Correct	7 ms	23908 KB	Output is correct
33	Correct	7 ms	23900 KB	Output is correct
34	Correct	7 ms	23900 KB	Output is correct
35	Correct	7 ms	23896 KB	Output is correct
36	Correct	8 ms	24148 KB	Output is correct
37	Correct	7 ms	24036 KB	Output is correct
38	Correct	8 ms	23900 KB	Output is correct
39	Correct	7 ms	23896 KB	Output is correct
40	Correct	7 ms	23900 KB	Output is correct
41	Correct	7 ms	23896 KB	Output is correct
42	Correct	7 ms	23896 KB	Output is correct
43	Correct	8 ms	23896 KB	Output is correct
44	Correct	7 ms	23900 KB	Output is correct
45	Correct	8 ms	23900 KB	Output is correct
46	Correct	8 ms	23896 KB	Output is correct
47	Correct	7 ms	23900 KB	Output is correct
48	Correct	7 ms	23900 KB	Output is correct
49	Correct	7 ms	24008 KB	Output is correct
50	Correct	7 ms	23896 KB	Output is correct
51	Correct	7 ms	23900 KB	Output is correct
52	Correct	7 ms	23984 KB	Output is correct
53	Correct	8 ms	23896 KB	Output is correct
54	Correct	8 ms	23908 KB	Output is correct
55	Correct	8 ms	23944 KB	Output is correct
56	Correct	7 ms	23940 KB	Output is correct
57	Correct	7 ms	23900 KB	Output is correct
58	Correct	8 ms	23900 KB	Output is correct

Subtask #3
37.0 / 37.0

#	결과	실행 시간	메모리	Grader output
1	Correct	7 ms	23900 KB	Output is correct
2	Correct	7 ms	23900 KB	Output is correct
3	Correct	7 ms	23896 KB	Output is correct
4	Correct	8 ms	23912 KB	Output is correct
5	Correct	7 ms	23900 KB	Output is correct
6	Correct	7 ms	23896 KB	Output is correct
7	Correct	8 ms	23900 KB	Output is correct
8	Correct	7 ms	23900 KB	Output is correct
9	Correct	7 ms	24152 KB	Output is correct
10	Correct	9 ms	23900 KB	Output is correct
11	Correct	7 ms	23900 KB	Output is correct
12	Correct	7 ms	23900 KB	Output is correct
13	Correct	7 ms	23912 KB	Output is correct
14	Correct	8 ms	23900 KB	Output is correct
15	Correct	7 ms	23900 KB	Output is correct
16	Correct	8 ms	23900 KB	Output is correct
17	Correct	7 ms	23900 KB	Output is correct
18	Correct	7 ms	23900 KB	Output is correct
19	Correct	7 ms	23900 KB	Output is correct
20	Correct	7 ms	23900 KB	Output is correct
21	Correct	8 ms	23900 KB	Output is correct
22	Correct	9 ms	23896 KB	Output is correct
23	Correct	8 ms	23900 KB	Output is correct
24	Correct	8 ms	23900 KB	Output is correct
25	Correct	8 ms	23900 KB	Output is correct
26	Correct	8 ms	23900 KB	Output is correct
27	Correct	8 ms	23900 KB	Output is correct
28	Correct	8 ms	23996 KB	Output is correct
29	Correct	7 ms	23900 KB	Output is correct
30	Correct	7 ms	23900 KB	Output is correct
31	Correct	7 ms	23900 KB	Output is correct
32	Correct	7 ms	23908 KB	Output is correct
33	Correct	7 ms	23900 KB	Output is correct
34	Correct	7 ms	23900 KB	Output is correct
35	Correct	7 ms	23896 KB	Output is correct
36	Correct	8 ms	24148 KB	Output is correct
37	Correct	7 ms	24036 KB	Output is correct
38	Correct	8 ms	23900 KB	Output is correct
39	Correct	7 ms	23896 KB	Output is correct
40	Correct	7 ms	23900 KB	Output is correct
41	Correct	7 ms	23896 KB	Output is correct
42	Correct	7 ms	23896 KB	Output is correct
43	Correct	8 ms	23896 KB	Output is correct
44	Correct	7 ms	23900 KB	Output is correct
45	Correct	8 ms	23900 KB	Output is correct
46	Correct	8 ms	23896 KB	Output is correct
47	Correct	7 ms	23900 KB	Output is correct
48	Correct	7 ms	23900 KB	Output is correct
49	Correct	7 ms	24008 KB	Output is correct
50	Correct	7 ms	23896 KB	Output is correct
51	Correct	7 ms	23900 KB	Output is correct
52	Correct	7 ms	23984 KB	Output is correct
53	Correct	8 ms	23896 KB	Output is correct
54	Correct	8 ms	23908 KB	Output is correct
55	Correct	8 ms	23944 KB	Output is correct
56	Correct	7 ms	23940 KB	Output is correct
57	Correct	7 ms	23900 KB	Output is correct
58	Correct	8 ms	23900 KB	Output is correct
59	Correct	384 ms	66648 KB	Output is correct
60	Correct	552 ms	71328 KB	Output is correct
61	Correct	7 ms	23900 KB	Output is correct
62	Correct	7 ms	23896 KB	Output is correct
63	Correct	319 ms	62156 KB	Output is correct
64	Correct	12 ms	24924 KB	Output is correct
65	Correct	20 ms	27740 KB	Output is correct
66	Correct	134 ms	56008 KB	Output is correct
67	Correct	664 ms	91044 KB	Output is correct
68	Correct	630 ms	92880 KB	Output is correct
69	Correct	13 ms	25432 KB	Output is correct
70	Correct	88 ms	40012 KB	Output is correct
71	Correct	376 ms	74172 KB	Output is correct
72	Correct	388 ms	72376 KB	Output is correct
73	Correct	80 ms	36048 KB	Output is correct
74	Correct	532 ms	68540 KB	Output is correct
75	Correct	30 ms	28972 KB	Output is correct
76	Correct	379 ms	72616 KB	Output is correct
77	Correct	361 ms	72872 KB	Output is correct
78	Correct	36 ms	30116 KB	Output is correct
79	Correct	673 ms	87096 KB	Output is correct
80	Correct	9 ms	24156 KB	Output is correct
81	Correct	105 ms	39620 KB	Output is correct
82	Correct	471 ms	71612 KB	Output is correct
83	Correct	540 ms	68528 KB	Output is correct
84	Correct	549 ms	68552 KB	Output is correct
85	Correct	526 ms	68468 KB	Output is correct
86	Correct	540 ms	70840 KB	Output is correct
87	Correct	520 ms	71196 KB	Output is correct

답안 #915026

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