Submission #592588

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
592588	2022-07-09T10:22:38 Z	ddy888	Network (BOI15_net)	C++17	100 / 100	423 ms	47660 KB

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define pb push_back
#define fi first
#define si second
#define ar array
typedef pair<int,int> pi;
typedef tuple<int,int,int> ti;  
template<typename T> bool chmin(T &a, T b){return (b < a) ? a = b, 1 : 0;}
template<typename T> bool chmax(T &a, T b){return (b > a) ? a = b, 1 : 0;}
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());

void debug_out() {cerr<<endl;}
template <typename Head, typename... Tail>
void debug_out(Head _H, Tail... _T) {cerr<<" "<<to_string(_H);debug_out(_T...);}
#define debug(...) cerr<<"["<<#__VA_ARGS__<<"]:",debug_out(__VA_ARGS__)

const int MAXN = 500010;

int n;
vector<int> g[MAXN];
vector<int> leaf;

void dfs(int x, int p) {
    if ((int)g[x].size() == 1) leaf.pb(x);
    for (auto i: g[x]) {
        if (i == p) continue;
        dfs(i, x);
    }
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    cin.exceptions(ios::badbit | ios::failbit);

    cin >> n;
    for (int i = 1; i < n; ++i) {
        int u, v; cin >> u >> v;
        g[u].pb(v);
        g[v].pb(u);
    }

    dfs(1, 1);

    int ans = ((int)leaf.size() + 1) / 2;
    cout << ans << '\n';

    if ((int)leaf.size() % 2) leaf.pb(leaf.front());
    int j = ans;
    for (int i = 0; i < ans; ++i) {
        cout << leaf[i] << ' ' << leaf[j++] << '\n';
    }

    return 0;
}

Subtask #1
18.0 / 18.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	6 ms	11988 KB	Output is correct
2	Correct	6 ms	11988 KB	Output is correct
3	Correct	8 ms	11972 KB	Output is correct
4	Correct	6 ms	11988 KB	Output is correct
5	Correct	6 ms	11988 KB	Output is correct
6	Correct	6 ms	11988 KB	Output is correct
7	Correct	6 ms	11988 KB	Output is correct
8	Correct	6 ms	11988 KB	Output is correct
9	Correct	8 ms	11988 KB	Output is correct
10	Correct	7 ms	12064 KB	Output is correct
11	Correct	7 ms	11988 KB	Output is correct
12	Correct	6 ms	11988 KB	Output is correct
13	Correct	8 ms	12116 KB	Output is correct
14	Correct	7 ms	11988 KB	Output is correct
15	Correct	7 ms	12076 KB	Output is correct
16	Correct	7 ms	11992 KB	Output is correct
17	Correct	7 ms	11988 KB	Output is correct
18	Correct	7 ms	12076 KB	Output is correct
19	Correct	6 ms	11988 KB	Output is correct
20	Correct	6 ms	12024 KB	Output is correct

Subtask #2
45.0 / 45.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	6 ms	11988 KB	Output is correct
2	Correct	6 ms	11988 KB	Output is correct
3	Correct	8 ms	11972 KB	Output is correct
4	Correct	6 ms	11988 KB	Output is correct
5	Correct	6 ms	11988 KB	Output is correct
6	Correct	6 ms	11988 KB	Output is correct
7	Correct	6 ms	11988 KB	Output is correct
8	Correct	6 ms	11988 KB	Output is correct
9	Correct	8 ms	11988 KB	Output is correct
10	Correct	7 ms	12064 KB	Output is correct
11	Correct	7 ms	11988 KB	Output is correct
12	Correct	6 ms	11988 KB	Output is correct
13	Correct	8 ms	12116 KB	Output is correct
14	Correct	7 ms	11988 KB	Output is correct
15	Correct	7 ms	12076 KB	Output is correct
16	Correct	7 ms	11992 KB	Output is correct
17	Correct	7 ms	11988 KB	Output is correct
18	Correct	7 ms	12076 KB	Output is correct
19	Correct	6 ms	11988 KB	Output is correct
20	Correct	6 ms	12024 KB	Output is correct
21	Correct	6 ms	12076 KB	Output is correct
22	Correct	8 ms	12148 KB	Output is correct
23	Correct	7 ms	12084 KB	Output is correct
24	Correct	7 ms	12088 KB	Output is correct
25	Correct	9 ms	12068 KB	Output is correct
26	Correct	8 ms	12048 KB	Output is correct
27	Correct	7 ms	12116 KB	Output is correct
28	Correct	7 ms	12116 KB	Output is correct
29	Correct	10 ms	12120 KB	Output is correct
30	Correct	6 ms	11988 KB	Output is correct
31	Correct	7 ms	12080 KB	Output is correct
32	Correct	6 ms	12052 KB	Output is correct
33	Correct	7 ms	11988 KB	Output is correct
34	Correct	6 ms	11988 KB	Output is correct
35	Correct	6 ms	11988 KB	Output is correct
36	Correct	7 ms	11968 KB	Output is correct
37	Correct	7 ms	11988 KB	Output is correct
38	Correct	8 ms	12044 KB	Output is correct
39	Correct	9 ms	11988 KB	Output is correct
40	Correct	7 ms	11984 KB	Output is correct
41	Correct	6 ms	11988 KB	Output is correct
42	Correct	6 ms	11988 KB	Output is correct
43	Correct	7 ms	12116 KB	Output is correct
44	Correct	7 ms	12076 KB	Output is correct
45	Correct	6 ms	11988 KB	Output is correct
46	Correct	6 ms	12060 KB	Output is correct
47	Correct	6 ms	11988 KB	Output is correct
48	Correct	7 ms	11988 KB	Output is correct
49	Correct	6 ms	12116 KB	Output is correct
50	Correct	7 ms	11988 KB	Output is correct
51	Correct	8 ms	12072 KB	Output is correct
52	Correct	8 ms	11988 KB	Output is correct
53	Correct	7 ms	12116 KB	Output is correct
54	Correct	7 ms	12024 KB	Output is correct
55	Correct	7 ms	12024 KB	Output is correct
56	Correct	6 ms	11988 KB	Output is correct
57	Correct	7 ms	12068 KB	Output is correct
58	Correct	9 ms	12088 KB	Output is correct

Subtask #3
37.0 / 37.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	6 ms	11988 KB	Output is correct
2	Correct	6 ms	11988 KB	Output is correct
3	Correct	8 ms	11972 KB	Output is correct
4	Correct	6 ms	11988 KB	Output is correct
5	Correct	6 ms	11988 KB	Output is correct
6	Correct	6 ms	11988 KB	Output is correct
7	Correct	6 ms	11988 KB	Output is correct
8	Correct	6 ms	11988 KB	Output is correct
9	Correct	8 ms	11988 KB	Output is correct
10	Correct	7 ms	12064 KB	Output is correct
11	Correct	7 ms	11988 KB	Output is correct
12	Correct	6 ms	11988 KB	Output is correct
13	Correct	8 ms	12116 KB	Output is correct
14	Correct	7 ms	11988 KB	Output is correct
15	Correct	7 ms	12076 KB	Output is correct
16	Correct	7 ms	11992 KB	Output is correct
17	Correct	7 ms	11988 KB	Output is correct
18	Correct	7 ms	12076 KB	Output is correct
19	Correct	6 ms	11988 KB	Output is correct
20	Correct	6 ms	12024 KB	Output is correct
21	Correct	6 ms	12076 KB	Output is correct
22	Correct	8 ms	12148 KB	Output is correct
23	Correct	7 ms	12084 KB	Output is correct
24	Correct	7 ms	12088 KB	Output is correct
25	Correct	9 ms	12068 KB	Output is correct
26	Correct	8 ms	12048 KB	Output is correct
27	Correct	7 ms	12116 KB	Output is correct
28	Correct	7 ms	12116 KB	Output is correct
29	Correct	10 ms	12120 KB	Output is correct
30	Correct	6 ms	11988 KB	Output is correct
31	Correct	7 ms	12080 KB	Output is correct
32	Correct	6 ms	12052 KB	Output is correct
33	Correct	7 ms	11988 KB	Output is correct
34	Correct	6 ms	11988 KB	Output is correct
35	Correct	6 ms	11988 KB	Output is correct
36	Correct	7 ms	11968 KB	Output is correct
37	Correct	7 ms	11988 KB	Output is correct
38	Correct	8 ms	12044 KB	Output is correct
39	Correct	9 ms	11988 KB	Output is correct
40	Correct	7 ms	11984 KB	Output is correct
41	Correct	6 ms	11988 KB	Output is correct
42	Correct	6 ms	11988 KB	Output is correct
43	Correct	7 ms	12116 KB	Output is correct
44	Correct	7 ms	12076 KB	Output is correct
45	Correct	6 ms	11988 KB	Output is correct
46	Correct	6 ms	12060 KB	Output is correct
47	Correct	6 ms	11988 KB	Output is correct
48	Correct	7 ms	11988 KB	Output is correct
49	Correct	6 ms	12116 KB	Output is correct
50	Correct	7 ms	11988 KB	Output is correct
51	Correct	8 ms	12072 KB	Output is correct
52	Correct	8 ms	11988 KB	Output is correct
53	Correct	7 ms	12116 KB	Output is correct
54	Correct	7 ms	12024 KB	Output is correct
55	Correct	7 ms	12024 KB	Output is correct
56	Correct	6 ms	11988 KB	Output is correct
57	Correct	7 ms	12068 KB	Output is correct
58	Correct	9 ms	12088 KB	Output is correct
59	Correct	297 ms	35980 KB	Output is correct
60	Correct	376 ms	38772 KB	Output is correct
61	Correct	7 ms	12076 KB	Output is correct
62	Correct	8 ms	12072 KB	Output is correct
63	Correct	240 ms	33552 KB	Output is correct
64	Correct	8 ms	12464 KB	Output is correct
65	Correct	15 ms	13880 KB	Output is correct
66	Correct	99 ms	27796 KB	Output is correct
67	Correct	423 ms	46808 KB	Output is correct
68	Correct	399 ms	47660 KB	Output is correct
69	Correct	12 ms	12884 KB	Output is correct
70	Correct	72 ms	21240 KB	Output is correct
71	Correct	235 ms	41876 KB	Output is correct
72	Correct	254 ms	40736 KB	Output is correct
73	Correct	68 ms	19084 KB	Output is correct
74	Correct	368 ms	37888 KB	Output is correct
75	Correct	32 ms	15220 KB	Output is correct
76	Correct	252 ms	41616 KB	Output is correct
77	Correct	254 ms	41596 KB	Output is correct
78	Correct	25 ms	15252 KB	Output is correct
79	Correct	413 ms	45180 KB	Output is correct
80	Correct	8 ms	12244 KB	Output is correct
81	Correct	102 ms	21408 KB	Output is correct
82	Correct	297 ms	39580 KB	Output is correct
83	Correct	368 ms	37648 KB	Output is correct
84	Correct	362 ms	37660 KB	Output is correct
85	Correct	336 ms	37804 KB	Output is correct
86	Correct	348 ms	38740 KB	Output is correct
87	Correct	346 ms	38728 KB	Output is correct

Submission #592588

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