Submission #486549

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
486549	2021-11-12T01:36:35 Z	Killer2501	Network (BOI15_net)	C++14	100 / 100	410 ms	76232 KB

#include<bits/stdc++.h>
#define pll pair<ll, ll>
#define fi first
#define se second
#define pb push_back
#define task "test"
#define pii pair<ll, pll>
using namespace std;
using ll = long long ;
const int  N = 5e5+5;
const ll mod = 1e9+7;
const ll base = 350;
const ll inf = 1e15;
ll m, n, t, k, a[N], b[N], ans, tong, d[N];
pll trave[N];
vector<ll> kq;
vector<ll> adj[N];
bool ok[N];
string s;
map<ll, ll> mp[N];
void add(ll& x, ll y, ll md)
{
	x += y;
	if(x >= md)x -= md;
}
ll pw(ll k, ll n, ll md)
{
	ll total = 1;
	for(; n; n >>= 1)
	{
		if(n&1)total = total * k % md;
		k = k * k % md;
	}
	return total;
}
void dfs(ll u, ll p)
{
	for(ll v: adj[u])
	{
		if(v == p)continue;
		dfs(v, u);
	}
	if(adj[u].size() == 1)kq.pb(u);
}
void sol()
{
    cin >> n;
    for(int i = 1; i < n; i ++)
	{
		ll x, y;
		cin >> x >> y;
		adj[x].pb(y);
		adj[y].pb(x);
	}
	dfs(1, 0);
	m = kq.size();
	cout << (m+1)/2 << '\n';
	for(int i = 0; i < m/2; i ++)cout << kq[i] <<" "<<kq[i+m/2] << '\n';
	if(m&1)cout << kq[m/2] <<" "<<kq.back();
}
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if(fopen(task".inp", "r"))
    {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int ntest = 1;
    //cin >> ntest;
    while(ntest -- > 0)
    sol();
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:68:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   68 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
net.cpp:69:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	17 ms	35532 KB	Output is correct
2	Correct	17 ms	35532 KB	Output is correct
3	Correct	17 ms	35532 KB	Output is correct
4	Correct	16 ms	35544 KB	Output is correct
5	Correct	17 ms	35472 KB	Output is correct
6	Correct	17 ms	35532 KB	Output is correct
7	Correct	18 ms	35524 KB	Output is correct
8	Correct	23 ms	35548 KB	Output is correct
9	Correct	17 ms	35428 KB	Output is correct
10	Correct	17 ms	35532 KB	Output is correct
11	Correct	19 ms	35660 KB	Output is correct
12	Correct	16 ms	35544 KB	Output is correct
13	Correct	18 ms	35552 KB	Output is correct
14	Correct	17 ms	35532 KB	Output is correct
15	Correct	17 ms	35520 KB	Output is correct
16	Correct	17 ms	35528 KB	Output is correct
17	Correct	18 ms	35548 KB	Output is correct
18	Correct	17 ms	35544 KB	Output is correct
19	Correct	17 ms	35448 KB	Output is correct
20	Correct	17 ms	35464 KB	Output is correct

Subtask #2
45.0 / 45.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	17 ms	35532 KB	Output is correct
2	Correct	17 ms	35532 KB	Output is correct
3	Correct	17 ms	35532 KB	Output is correct
4	Correct	16 ms	35544 KB	Output is correct
5	Correct	17 ms	35472 KB	Output is correct
6	Correct	17 ms	35532 KB	Output is correct
7	Correct	18 ms	35524 KB	Output is correct
8	Correct	23 ms	35548 KB	Output is correct
9	Correct	17 ms	35428 KB	Output is correct
10	Correct	17 ms	35532 KB	Output is correct
11	Correct	19 ms	35660 KB	Output is correct
12	Correct	16 ms	35544 KB	Output is correct
13	Correct	18 ms	35552 KB	Output is correct
14	Correct	17 ms	35532 KB	Output is correct
15	Correct	17 ms	35520 KB	Output is correct
16	Correct	17 ms	35528 KB	Output is correct
17	Correct	18 ms	35548 KB	Output is correct
18	Correct	17 ms	35544 KB	Output is correct
19	Correct	17 ms	35448 KB	Output is correct
20	Correct	17 ms	35464 KB	Output is correct
21	Correct	17 ms	35532 KB	Output is correct
22	Correct	20 ms	35656 KB	Output is correct
23	Correct	17 ms	35672 KB	Output is correct
24	Correct	18 ms	35696 KB	Output is correct
25	Correct	18 ms	35632 KB	Output is correct
26	Correct	18 ms	35620 KB	Output is correct
27	Correct	18 ms	35668 KB	Output is correct
28	Correct	18 ms	35680 KB	Output is correct
29	Correct	18 ms	35532 KB	Output is correct
30	Correct	17 ms	35428 KB	Output is correct
31	Correct	18 ms	35676 KB	Output is correct
32	Correct	17 ms	35476 KB	Output is correct
33	Correct	17 ms	35452 KB	Output is correct
34	Correct	17 ms	35464 KB	Output is correct
35	Correct	19 ms	35532 KB	Output is correct
36	Correct	17 ms	35440 KB	Output is correct
37	Correct	17 ms	35520 KB	Output is correct
38	Correct	18 ms	35520 KB	Output is correct
39	Correct	17 ms	35552 KB	Output is correct
40	Correct	18 ms	35532 KB	Output is correct
41	Correct	17 ms	35492 KB	Output is correct
42	Correct	18 ms	35532 KB	Output is correct
43	Correct	17 ms	35608 KB	Output is correct
44	Correct	18 ms	35532 KB	Output is correct
45	Correct	17 ms	35556 KB	Output is correct
46	Correct	20 ms	35604 KB	Output is correct
47	Correct	17 ms	35432 KB	Output is correct
48	Correct	20 ms	35568 KB	Output is correct
49	Correct	17 ms	35532 KB	Output is correct
50	Correct	20 ms	35484 KB	Output is correct
51	Correct	17 ms	35516 KB	Output is correct
52	Correct	17 ms	35496 KB	Output is correct
53	Correct	17 ms	35532 KB	Output is correct
54	Correct	17 ms	35560 KB	Output is correct
55	Correct	18 ms	35532 KB	Output is correct
56	Correct	17 ms	35532 KB	Output is correct
57	Correct	17 ms	35532 KB	Output is correct
58	Correct	18 ms	35660 KB	Output is correct

Subtask #3
37.0 / 37.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	17 ms	35532 KB	Output is correct
2	Correct	17 ms	35532 KB	Output is correct
3	Correct	17 ms	35532 KB	Output is correct
4	Correct	16 ms	35544 KB	Output is correct
5	Correct	17 ms	35472 KB	Output is correct
6	Correct	17 ms	35532 KB	Output is correct
7	Correct	18 ms	35524 KB	Output is correct
8	Correct	23 ms	35548 KB	Output is correct
9	Correct	17 ms	35428 KB	Output is correct
10	Correct	17 ms	35532 KB	Output is correct
11	Correct	19 ms	35660 KB	Output is correct
12	Correct	16 ms	35544 KB	Output is correct
13	Correct	18 ms	35552 KB	Output is correct
14	Correct	17 ms	35532 KB	Output is correct
15	Correct	17 ms	35520 KB	Output is correct
16	Correct	17 ms	35528 KB	Output is correct
17	Correct	18 ms	35548 KB	Output is correct
18	Correct	17 ms	35544 KB	Output is correct
19	Correct	17 ms	35448 KB	Output is correct
20	Correct	17 ms	35464 KB	Output is correct
21	Correct	17 ms	35532 KB	Output is correct
22	Correct	20 ms	35656 KB	Output is correct
23	Correct	17 ms	35672 KB	Output is correct
24	Correct	18 ms	35696 KB	Output is correct
25	Correct	18 ms	35632 KB	Output is correct
26	Correct	18 ms	35620 KB	Output is correct
27	Correct	18 ms	35668 KB	Output is correct
28	Correct	18 ms	35680 KB	Output is correct
29	Correct	18 ms	35532 KB	Output is correct
30	Correct	17 ms	35428 KB	Output is correct
31	Correct	18 ms	35676 KB	Output is correct
32	Correct	17 ms	35476 KB	Output is correct
33	Correct	17 ms	35452 KB	Output is correct
34	Correct	17 ms	35464 KB	Output is correct
35	Correct	19 ms	35532 KB	Output is correct
36	Correct	17 ms	35440 KB	Output is correct
37	Correct	17 ms	35520 KB	Output is correct
38	Correct	18 ms	35520 KB	Output is correct
39	Correct	17 ms	35552 KB	Output is correct
40	Correct	18 ms	35532 KB	Output is correct
41	Correct	17 ms	35492 KB	Output is correct
42	Correct	18 ms	35532 KB	Output is correct
43	Correct	17 ms	35608 KB	Output is correct
44	Correct	18 ms	35532 KB	Output is correct
45	Correct	17 ms	35556 KB	Output is correct
46	Correct	20 ms	35604 KB	Output is correct
47	Correct	17 ms	35432 KB	Output is correct
48	Correct	20 ms	35568 KB	Output is correct
49	Correct	17 ms	35532 KB	Output is correct
50	Correct	20 ms	35484 KB	Output is correct
51	Correct	17 ms	35516 KB	Output is correct
52	Correct	17 ms	35496 KB	Output is correct
53	Correct	17 ms	35532 KB	Output is correct
54	Correct	17 ms	35560 KB	Output is correct
55	Correct	18 ms	35532 KB	Output is correct
56	Correct	17 ms	35532 KB	Output is correct
57	Correct	17 ms	35532 KB	Output is correct
58	Correct	18 ms	35660 KB	Output is correct
59	Correct	301 ms	63980 KB	Output is correct
60	Correct	378 ms	66816 KB	Output is correct
61	Correct	20 ms	35532 KB	Output is correct
62	Correct	17 ms	35452 KB	Output is correct
63	Correct	258 ms	60196 KB	Output is correct
64	Correct	20 ms	36020 KB	Output is correct
65	Correct	26 ms	37744 KB	Output is correct
66	Correct	118 ms	54024 KB	Output is correct
67	Correct	406 ms	74584 KB	Output is correct
68	Correct	410 ms	76232 KB	Output is correct
69	Correct	21 ms	36556 KB	Output is correct
70	Correct	77 ms	46784 KB	Output is correct
71	Correct	251 ms	69240 KB	Output is correct
72	Correct	260 ms	68052 KB	Output is correct
73	Correct	76 ms	43532 KB	Output is correct
74	Correct	359 ms	64688 KB	Output is correct
75	Correct	34 ms	39100 KB	Output is correct
76	Correct	249 ms	68796 KB	Output is correct
77	Correct	240 ms	69016 KB	Output is correct
78	Correct	37 ms	39364 KB	Output is correct
79	Correct	400 ms	72260 KB	Output is correct
80	Correct	18 ms	35788 KB	Output is correct
81	Correct	89 ms	45936 KB	Output is correct
82	Correct	301 ms	66640 KB	Output is correct
83	Correct	361 ms	64604 KB	Output is correct
84	Correct	349 ms	64560 KB	Output is correct
85	Correct	367 ms	64692 KB	Output is correct
86	Correct	366 ms	66868 KB	Output is correct
87	Correct	373 ms	66880 KB	Output is correct

Submission #486549

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