#include <bits/stdc++.h>
using namespace std ;
#define nn "\n"
#define x_x ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define intt int t; cin>>t; while(t--)
#define emp emplace_back
#define mod 1000000007
#define all(v) v.begin(), v.end()
#define sz(x) (int)x.size()
//#define a first
//#define b second
typedef long long ll;
vector<int>v;
void dfs(int i, int p, vector<int>adj[])
{
if(sz(adj[i])==1){v.emp(i); return ;}
for(auto j:adj[i])
if(j!=p)dfs(j,i,adj);
}
void mxx(int i, int p, vector<int>adj[], int&ind ,int&mx, int dis=0)
{
if(sz(adj[i])==1&&i!=ind)
{
if(dis>mx)ind=i,mx=dis; return ;
}
for(auto j:adj[i])
if(j!=p)mxx(j,i,adj, ind, mx, dis+1);
}
int main()
{
x_x
int n; cin>>n; vector<int>adj[n+2]; for(int i=1,x,y; i<n;i++)cin>>x>>y, adj[x].emp(y), adj[y].emp(x);
int mx=0,ind=1;
for(int i=1; i<=n; i++)if(sz(adj[i])>mx)mx=sz(adj[i]), ind=i;
dfs(ind,0,adj);
cout<<(sz(v)+1)/2<<nn;
for(int i=0; i<sz(v)/2; i++)cout<<v[i]<<' '<<v[i+(sz(v)/2)]<<nn;
if(sz(v)%2)
{
ind=mx=0; cout<<v.back()<<' '; ind=v.back(); mxx(v.back(),0,adj,ind,mx); cout<<ind;
}
return 0;
}
Compilation message
net.cpp: In function 'void mxx(int, int, std::vector<int>*, int&, int&, int)':
net.cpp:24:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
24 | if(dis>mx)ind=i,mx=dis; return ;
| ^~
net.cpp:24:33: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
24 | if(dis>mx)ind=i,mx=dis; return ;
| ^~~~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
320 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
324 KB |
Output is correct |
5 |
Correct |
0 ms |
212 KB |
Output is correct |
6 |
Correct |
1 ms |
212 KB |
Output is correct |
7 |
Correct |
1 ms |
212 KB |
Output is correct |
8 |
Correct |
0 ms |
212 KB |
Output is correct |
9 |
Correct |
1 ms |
212 KB |
Output is correct |
10 |
Correct |
0 ms |
212 KB |
Output is correct |
11 |
Correct |
0 ms |
212 KB |
Output is correct |
12 |
Correct |
0 ms |
212 KB |
Output is correct |
13 |
Correct |
1 ms |
324 KB |
Output is correct |
14 |
Correct |
0 ms |
212 KB |
Output is correct |
15 |
Correct |
0 ms |
212 KB |
Output is correct |
16 |
Correct |
0 ms |
212 KB |
Output is correct |
17 |
Correct |
0 ms |
212 KB |
Output is correct |
18 |
Correct |
0 ms |
316 KB |
Output is correct |
19 |
Correct |
0 ms |
320 KB |
Output is correct |
20 |
Correct |
1 ms |
212 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
320 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
324 KB |
Output is correct |
5 |
Correct |
0 ms |
212 KB |
Output is correct |
6 |
Correct |
1 ms |
212 KB |
Output is correct |
7 |
Correct |
1 ms |
212 KB |
Output is correct |
8 |
Correct |
0 ms |
212 KB |
Output is correct |
9 |
Correct |
1 ms |
212 KB |
Output is correct |
10 |
Correct |
0 ms |
212 KB |
Output is correct |
11 |
Correct |
0 ms |
212 KB |
Output is correct |
12 |
Correct |
0 ms |
212 KB |
Output is correct |
13 |
Correct |
1 ms |
324 KB |
Output is correct |
14 |
Correct |
0 ms |
212 KB |
Output is correct |
15 |
Correct |
0 ms |
212 KB |
Output is correct |
16 |
Correct |
0 ms |
212 KB |
Output is correct |
17 |
Correct |
0 ms |
212 KB |
Output is correct |
18 |
Correct |
0 ms |
316 KB |
Output is correct |
19 |
Correct |
0 ms |
320 KB |
Output is correct |
20 |
Correct |
1 ms |
212 KB |
Output is correct |
21 |
Correct |
0 ms |
212 KB |
Output is correct |
22 |
Correct |
1 ms |
468 KB |
Output is correct |
23 |
Correct |
1 ms |
468 KB |
Output is correct |
24 |
Correct |
1 ms |
468 KB |
Output is correct |
25 |
Correct |
1 ms |
340 KB |
Output is correct |
26 |
Correct |
1 ms |
340 KB |
Output is correct |
27 |
Correct |
1 ms |
460 KB |
Output is correct |
28 |
Correct |
1 ms |
468 KB |
Output is correct |
29 |
Correct |
1 ms |
340 KB |
Output is correct |
30 |
Correct |
0 ms |
212 KB |
Output is correct |
31 |
Correct |
1 ms |
416 KB |
Output is correct |
32 |
Correct |
1 ms |
212 KB |
Output is correct |
33 |
Correct |
1 ms |
212 KB |
Output is correct |
34 |
Correct |
1 ms |
212 KB |
Output is correct |
35 |
Correct |
0 ms |
324 KB |
Output is correct |
36 |
Correct |
0 ms |
312 KB |
Output is correct |
37 |
Correct |
0 ms |
340 KB |
Output is correct |
38 |
Correct |
1 ms |
340 KB |
Output is correct |
39 |
Correct |
0 ms |
212 KB |
Output is correct |
40 |
Correct |
1 ms |
212 KB |
Output is correct |
41 |
Correct |
0 ms |
212 KB |
Output is correct |
42 |
Correct |
1 ms |
340 KB |
Output is correct |
43 |
Correct |
1 ms |
340 KB |
Output is correct |
44 |
Correct |
1 ms |
212 KB |
Output is correct |
45 |
Correct |
1 ms |
320 KB |
Output is correct |
46 |
Correct |
1 ms |
340 KB |
Output is correct |
47 |
Correct |
0 ms |
212 KB |
Output is correct |
48 |
Correct |
1 ms |
340 KB |
Output is correct |
49 |
Correct |
1 ms |
328 KB |
Output is correct |
50 |
Correct |
1 ms |
212 KB |
Output is correct |
51 |
Correct |
0 ms |
212 KB |
Output is correct |
52 |
Correct |
0 ms |
340 KB |
Output is correct |
53 |
Correct |
1 ms |
340 KB |
Output is correct |
54 |
Correct |
0 ms |
212 KB |
Output is correct |
55 |
Correct |
1 ms |
340 KB |
Output is correct |
56 |
Correct |
1 ms |
320 KB |
Output is correct |
57 |
Correct |
1 ms |
340 KB |
Output is correct |
58 |
Correct |
1 ms |
468 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
320 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Correct |
0 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
324 KB |
Output is correct |
5 |
Correct |
0 ms |
212 KB |
Output is correct |
6 |
Correct |
1 ms |
212 KB |
Output is correct |
7 |
Correct |
1 ms |
212 KB |
Output is correct |
8 |
Correct |
0 ms |
212 KB |
Output is correct |
9 |
Correct |
1 ms |
212 KB |
Output is correct |
10 |
Correct |
0 ms |
212 KB |
Output is correct |
11 |
Correct |
0 ms |
212 KB |
Output is correct |
12 |
Correct |
0 ms |
212 KB |
Output is correct |
13 |
Correct |
1 ms |
324 KB |
Output is correct |
14 |
Correct |
0 ms |
212 KB |
Output is correct |
15 |
Correct |
0 ms |
212 KB |
Output is correct |
16 |
Correct |
0 ms |
212 KB |
Output is correct |
17 |
Correct |
0 ms |
212 KB |
Output is correct |
18 |
Correct |
0 ms |
316 KB |
Output is correct |
19 |
Correct |
0 ms |
320 KB |
Output is correct |
20 |
Correct |
1 ms |
212 KB |
Output is correct |
21 |
Correct |
0 ms |
212 KB |
Output is correct |
22 |
Correct |
1 ms |
468 KB |
Output is correct |
23 |
Correct |
1 ms |
468 KB |
Output is correct |
24 |
Correct |
1 ms |
468 KB |
Output is correct |
25 |
Correct |
1 ms |
340 KB |
Output is correct |
26 |
Correct |
1 ms |
340 KB |
Output is correct |
27 |
Correct |
1 ms |
460 KB |
Output is correct |
28 |
Correct |
1 ms |
468 KB |
Output is correct |
29 |
Correct |
1 ms |
340 KB |
Output is correct |
30 |
Correct |
0 ms |
212 KB |
Output is correct |
31 |
Correct |
1 ms |
416 KB |
Output is correct |
32 |
Correct |
1 ms |
212 KB |
Output is correct |
33 |
Correct |
1 ms |
212 KB |
Output is correct |
34 |
Correct |
1 ms |
212 KB |
Output is correct |
35 |
Correct |
0 ms |
324 KB |
Output is correct |
36 |
Correct |
0 ms |
312 KB |
Output is correct |
37 |
Correct |
0 ms |
340 KB |
Output is correct |
38 |
Correct |
1 ms |
340 KB |
Output is correct |
39 |
Correct |
0 ms |
212 KB |
Output is correct |
40 |
Correct |
1 ms |
212 KB |
Output is correct |
41 |
Correct |
0 ms |
212 KB |
Output is correct |
42 |
Correct |
1 ms |
340 KB |
Output is correct |
43 |
Correct |
1 ms |
340 KB |
Output is correct |
44 |
Correct |
1 ms |
212 KB |
Output is correct |
45 |
Correct |
1 ms |
320 KB |
Output is correct |
46 |
Correct |
1 ms |
340 KB |
Output is correct |
47 |
Correct |
0 ms |
212 KB |
Output is correct |
48 |
Correct |
1 ms |
340 KB |
Output is correct |
49 |
Correct |
1 ms |
328 KB |
Output is correct |
50 |
Correct |
1 ms |
212 KB |
Output is correct |
51 |
Correct |
0 ms |
212 KB |
Output is correct |
52 |
Correct |
0 ms |
340 KB |
Output is correct |
53 |
Correct |
1 ms |
340 KB |
Output is correct |
54 |
Correct |
0 ms |
212 KB |
Output is correct |
55 |
Correct |
1 ms |
340 KB |
Output is correct |
56 |
Correct |
1 ms |
320 KB |
Output is correct |
57 |
Correct |
1 ms |
340 KB |
Output is correct |
58 |
Correct |
1 ms |
468 KB |
Output is correct |
59 |
Correct |
270 ms |
34792 KB |
Output is correct |
60 |
Correct |
380 ms |
38764 KB |
Output is correct |
61 |
Correct |
0 ms |
324 KB |
Output is correct |
62 |
Correct |
1 ms |
212 KB |
Output is correct |
63 |
Correct |
270 ms |
31208 KB |
Output is correct |
64 |
Correct |
2 ms |
852 KB |
Output is correct |
65 |
Correct |
12 ms |
2788 KB |
Output is correct |
66 |
Correct |
107 ms |
19000 KB |
Output is correct |
67 |
Correct |
384 ms |
51136 KB |
Output is correct |
68 |
Correct |
394 ms |
63100 KB |
Output is correct |
69 |
Correct |
6 ms |
1468 KB |
Output is correct |
70 |
Correct |
64 ms |
13252 KB |
Output is correct |
71 |
Correct |
250 ms |
41880 KB |
Output is correct |
72 |
Correct |
262 ms |
40660 KB |
Output is correct |
73 |
Correct |
70 ms |
10612 KB |
Output is correct |
74 |
Correct |
332 ms |
37696 KB |
Output is correct |
75 |
Correct |
18 ms |
4820 KB |
Output is correct |
76 |
Correct |
240 ms |
41568 KB |
Output is correct |
77 |
Correct |
234 ms |
41596 KB |
Output is correct |
78 |
Correct |
23 ms |
5964 KB |
Output is correct |
79 |
Correct |
553 ms |
60408 KB |
Output is correct |
80 |
Correct |
2 ms |
596 KB |
Output is correct |
81 |
Correct |
74 ms |
13496 KB |
Output is correct |
82 |
Correct |
334 ms |
39584 KB |
Output is correct |
83 |
Correct |
373 ms |
37700 KB |
Output is correct |
84 |
Correct |
344 ms |
37612 KB |
Output is correct |
85 |
Correct |
340 ms |
37708 KB |
Output is correct |
86 |
Correct |
367 ms |
38788 KB |
Output is correct |
87 |
Correct |
354 ms |
38760 KB |
Output is correct |