Submission #394607

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
394607	2021-04-27T05:47:48 Z	amirmohammad_nezami	Network (BOI15_net)	C++14	100 / 100	531 ms	58824 KB

//                                                          In the name of God 
//                                           We are everywhere while we are nowhere(Haj NEZAM...)
#include <bits/stdc++.h>
using namespace std;

#define F first
#define S second
#define lc 2 * v
#define rc 2 * v + 1
#define PB push_back
#define MP make_pair
#define ll long long
#define int long long
#define ld long double
#define mid (s + e) / 2
#define pii pair <int , int>
#define _sz(e) (int)e.size()
#define _all(e) e.begin() , e.end()
#define pll pair <long long , long long>
#define piii pair <int , pair <int , int> >
#define FAST ios::sync_with_stdio(0);cin.tie(0)
#define UNI(e) e.resize(unique(_all(e)) - e.begin())

#define kill(e) cout << e << '\n'

#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")

const int maxn = 5e5 + 5 , N = 1e6 + 5 , SQ = 450 , base = 800287 , mod = 1e9 + 7 , INF = 1e9 + 5 , lg = 20;
const ld eps = 1e-4;

int n , root;
vector <int> vec;
vector <int> edges[maxn];

void dfs(int v , int p = -1) {
	if(_sz(edges[v]) == 1) {
		vec.PB(v);
	}

	for (auto u : edges[v]) {
		if(u != p) {
			dfs(u , v);
		}
	}
}

int32_t main() {
	FAST;
	cin >> n;
	for (int i = 0; i < n - 1; ++i) {
		int x , y; cin >> x >> y;
		x-- , y--;
		edges[x].PB(y);
		edges[y].PB(x);
	}
	for (int i = 0; i < n; ++i) {
		if(_sz(edges[i]) > 1) {root = i;}
	}
	dfs(root);
	
	int ans = (_sz(vec) + 1) / 2;
	cout << ans << '\n';
	for (int i = 0; i < ans; ++i) {
		int nxt = min(_sz(vec) - 1 , i + ans);
		cout << vec[i] + 1 << ' ' << vec[nxt] + 1 << '\n';
	}
}
 // Mistakes:
//  * Read the problem carefully.
//  * Check maxn.
//  * Overflows.

Subtask #1
18.0 / 18.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	7 ms	11980 KB	Output is correct
2	Correct	7 ms	12056 KB	Output is correct
3	Correct	6 ms	11980 KB	Output is correct
4	Correct	7 ms	11980 KB	Output is correct
5	Correct	6 ms	11980 KB	Output is correct
6	Correct	7 ms	11980 KB	Output is correct
7	Correct	7 ms	11980 KB	Output is correct
8	Correct	8 ms	11984 KB	Output is correct
9	Correct	7 ms	11980 KB	Output is correct
10	Correct	8 ms	11980 KB	Output is correct
11	Correct	6 ms	11980 KB	Output is correct
12	Correct	7 ms	11980 KB	Output is correct
13	Correct	7 ms	11980 KB	Output is correct
14	Correct	7 ms	11996 KB	Output is correct
15	Correct	7 ms	11980 KB	Output is correct
16	Correct	7 ms	11980 KB	Output is correct
17	Correct	7 ms	11980 KB	Output is correct
18	Correct	7 ms	11980 KB	Output is correct
19	Correct	7 ms	11980 KB	Output is correct
20	Correct	7 ms	11980 KB	Output is correct

Subtask #2
45.0 / 45.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	7 ms	11980 KB	Output is correct
2	Correct	7 ms	12056 KB	Output is correct
3	Correct	6 ms	11980 KB	Output is correct
4	Correct	7 ms	11980 KB	Output is correct
5	Correct	6 ms	11980 KB	Output is correct
6	Correct	7 ms	11980 KB	Output is correct
7	Correct	7 ms	11980 KB	Output is correct
8	Correct	8 ms	11984 KB	Output is correct
9	Correct	7 ms	11980 KB	Output is correct
10	Correct	8 ms	11980 KB	Output is correct
11	Correct	6 ms	11980 KB	Output is correct
12	Correct	7 ms	11980 KB	Output is correct
13	Correct	7 ms	11980 KB	Output is correct
14	Correct	7 ms	11996 KB	Output is correct
15	Correct	7 ms	11980 KB	Output is correct
16	Correct	7 ms	11980 KB	Output is correct
17	Correct	7 ms	11980 KB	Output is correct
18	Correct	7 ms	11980 KB	Output is correct
19	Correct	7 ms	11980 KB	Output is correct
20	Correct	7 ms	11980 KB	Output is correct
21	Correct	7 ms	11984 KB	Output is correct
22	Correct	8 ms	12108 KB	Output is correct
23	Correct	9 ms	12108 KB	Output is correct
24	Correct	8 ms	12096 KB	Output is correct
25	Correct	7 ms	12100 KB	Output is correct
26	Correct	7 ms	12112 KB	Output is correct
27	Correct	8 ms	12108 KB	Output is correct
28	Correct	8 ms	12108 KB	Output is correct
29	Correct	8 ms	12108 KB	Output is correct
30	Correct	7 ms	11980 KB	Output is correct
31	Correct	8 ms	12108 KB	Output is correct
32	Correct	7 ms	12044 KB	Output is correct
33	Correct	7 ms	11980 KB	Output is correct
34	Correct	7 ms	11984 KB	Output is correct
35	Correct	8 ms	11980 KB	Output is correct
36	Correct	7 ms	11984 KB	Output is correct
37	Correct	8 ms	11980 KB	Output is correct
38	Correct	8 ms	12108 KB	Output is correct
39	Correct	7 ms	11980 KB	Output is correct
40	Correct	7 ms	11980 KB	Output is correct
41	Correct	7 ms	11980 KB	Output is correct
42	Correct	7 ms	11980 KB	Output is correct
43	Correct	8 ms	12108 KB	Output is correct
44	Correct	7 ms	11980 KB	Output is correct
45	Correct	7 ms	11992 KB	Output is correct
46	Correct	7 ms	11980 KB	Output is correct
47	Correct	7 ms	11980 KB	Output is correct
48	Correct	8 ms	12072 KB	Output is correct
49	Correct	7 ms	12108 KB	Output is correct
50	Correct	7 ms	11980 KB	Output is correct
51	Correct	7 ms	11980 KB	Output is correct
52	Correct	7 ms	11980 KB	Output is correct
53	Correct	7 ms	12080 KB	Output is correct
54	Correct	7 ms	11980 KB	Output is correct
55	Correct	7 ms	11980 KB	Output is correct
56	Correct	8 ms	11980 KB	Output is correct
57	Correct	7 ms	11980 KB	Output is correct
58	Correct	10 ms	12108 KB	Output is correct

Subtask #3
37.0 / 37.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	7 ms	11980 KB	Output is correct
2	Correct	7 ms	12056 KB	Output is correct
3	Correct	6 ms	11980 KB	Output is correct
4	Correct	7 ms	11980 KB	Output is correct
5	Correct	6 ms	11980 KB	Output is correct
6	Correct	7 ms	11980 KB	Output is correct
7	Correct	7 ms	11980 KB	Output is correct
8	Correct	8 ms	11984 KB	Output is correct
9	Correct	7 ms	11980 KB	Output is correct
10	Correct	8 ms	11980 KB	Output is correct
11	Correct	6 ms	11980 KB	Output is correct
12	Correct	7 ms	11980 KB	Output is correct
13	Correct	7 ms	11980 KB	Output is correct
14	Correct	7 ms	11996 KB	Output is correct
15	Correct	7 ms	11980 KB	Output is correct
16	Correct	7 ms	11980 KB	Output is correct
17	Correct	7 ms	11980 KB	Output is correct
18	Correct	7 ms	11980 KB	Output is correct
19	Correct	7 ms	11980 KB	Output is correct
20	Correct	7 ms	11980 KB	Output is correct
21	Correct	7 ms	11984 KB	Output is correct
22	Correct	8 ms	12108 KB	Output is correct
23	Correct	9 ms	12108 KB	Output is correct
24	Correct	8 ms	12096 KB	Output is correct
25	Correct	7 ms	12100 KB	Output is correct
26	Correct	7 ms	12112 KB	Output is correct
27	Correct	8 ms	12108 KB	Output is correct
28	Correct	8 ms	12108 KB	Output is correct
29	Correct	8 ms	12108 KB	Output is correct
30	Correct	7 ms	11980 KB	Output is correct
31	Correct	8 ms	12108 KB	Output is correct
32	Correct	7 ms	12044 KB	Output is correct
33	Correct	7 ms	11980 KB	Output is correct
34	Correct	7 ms	11984 KB	Output is correct
35	Correct	8 ms	11980 KB	Output is correct
36	Correct	7 ms	11984 KB	Output is correct
37	Correct	8 ms	11980 KB	Output is correct
38	Correct	8 ms	12108 KB	Output is correct
39	Correct	7 ms	11980 KB	Output is correct
40	Correct	7 ms	11980 KB	Output is correct
41	Correct	7 ms	11980 KB	Output is correct
42	Correct	7 ms	11980 KB	Output is correct
43	Correct	8 ms	12108 KB	Output is correct
44	Correct	7 ms	11980 KB	Output is correct
45	Correct	7 ms	11992 KB	Output is correct
46	Correct	7 ms	11980 KB	Output is correct
47	Correct	7 ms	11980 KB	Output is correct
48	Correct	8 ms	12072 KB	Output is correct
49	Correct	7 ms	12108 KB	Output is correct
50	Correct	7 ms	11980 KB	Output is correct
51	Correct	7 ms	11980 KB	Output is correct
52	Correct	7 ms	11980 KB	Output is correct
53	Correct	7 ms	12080 KB	Output is correct
54	Correct	7 ms	11980 KB	Output is correct
55	Correct	7 ms	11980 KB	Output is correct
56	Correct	8 ms	11980 KB	Output is correct
57	Correct	7 ms	11980 KB	Output is correct
58	Correct	10 ms	12108 KB	Output is correct
59	Correct	409 ms	34524 KB	Output is correct
60	Correct	416 ms	36780 KB	Output is correct
61	Correct	7 ms	11980 KB	Output is correct
62	Correct	7 ms	11980 KB	Output is correct
63	Correct	327 ms	31512 KB	Output is correct
64	Correct	9 ms	12428 KB	Output is correct
65	Correct	17 ms	13688 KB	Output is correct
66	Correct	172 ms	24556 KB	Output is correct
67	Correct	531 ms	58824 KB	Output is correct
68	Correct	523 ms	50060 KB	Output is correct
69	Correct	15 ms	12876 KB	Output is correct
70	Correct	112 ms	21148 KB	Output is correct
71	Correct	324 ms	39020 KB	Output is correct
72	Correct	348 ms	37984 KB	Output is correct
73	Correct	98 ms	18324 KB	Output is correct
74	Correct	480 ms	34440 KB	Output is correct
75	Correct	30 ms	15064 KB	Output is correct
76	Correct	366 ms	38552 KB	Output is correct
77	Correct	322 ms	39072 KB	Output is correct
78	Correct	35 ms	15364 KB	Output is correct
79	Correct	519 ms	42016 KB	Output is correct
80	Correct	9 ms	12236 KB	Output is correct
81	Correct	121 ms	20584 KB	Output is correct
82	Correct	405 ms	36784 KB	Output is correct
83	Correct	523 ms	34436 KB	Output is correct
84	Correct	485 ms	34488 KB	Output is correct
85	Correct	514 ms	34464 KB	Output is correct
86	Correct	455 ms	36784 KB	Output is correct
87	Correct	507 ms	36740 KB	Output is correct

Submission #394607

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