#include<bits/stdc++.h>
using namespace std;
const int N = 500001;
bool visited[N];
int LeavesInsubtee[N];
vector<int> adj[N];
vector<int> res[N];
int n;
int ans = 0;
int cur_ans = 0;
int subtreeValue = 0;
void dfs(int u){
visited[u] = true;
if((int)adj[u].size() == 1){
LeavesInsubtee[u] = 1;
}
for(int v : adj[u]){
if(!visited[v]){
dfs(v);
LeavesInsubtee[u] += LeavesInsubtee[v];
}
}
}
void dfs2(int u){
visited[u] = true;
if((int)adj[u].size() == 1){
res[subtreeValue].push_back(u);
}
for(int v : adj[u]){
if(!visited[v]){
dfs2(v);
}
}
}
int cutlocation(int u){
visited[u] = true;
for(int v : adj[u]){
if(!visited[v]){
if(LeavesInsubtee[v] > floor((cur_ans)/2)){
return cutlocation(v);
}
}
}
return u;
}
int cut(int u){
dfs(1);
for(int i = 1; i <= n; i++){
visited[i] = false;
}
int x = cutlocation(1);
for(int i = 1; i <= n; i++){
visited[i] = false;
}
visited[x] = true;
for(int v : adj[x]){
subtreeValue++;
dfs2(v);
}
return x;
}
int main(){
cin >> n;
for(int i = 0; i < n - 1; i++){
int a, b;
cin >> a >> b;
adj[a].push_back(b);
adj[b].push_back(a);
}
for(int i = 1; i <= n; i++){
if((int)adj[i].size() == 1){
ans++;
}
}
cur_ans = ans;
ans = (ans + 1)/2;
cout << ans << "\n";
cut(n);
vector<int> finalAns(2 * ans);
int idx = 0;
for(int i = 1; i <= subtreeValue; i++){
for(int j = 0; j < (int)res[i].size(); j++){
finalAns[idx] = res[i][j];
idx += 2;
if(idx == 2 * ans){
idx = 1;
}
}
}
if(!(finalAns.empty()) && finalAns.back() == 0){
finalAns.back() = res[1][0];
}
for(int i = 0; i < (int)finalAns.size(); i += 2){
cout << finalAns[i] << " " << finalAns[i + 1] << "\n";
}
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
12 ms |
23764 KB |
Output is correct |
2 |
Correct |
11 ms |
23696 KB |
Output is correct |
3 |
Correct |
11 ms |
23764 KB |
Output is correct |
4 |
Correct |
13 ms |
23728 KB |
Output is correct |
5 |
Correct |
12 ms |
23764 KB |
Output is correct |
6 |
Correct |
12 ms |
23764 KB |
Output is correct |
7 |
Correct |
11 ms |
23764 KB |
Output is correct |
8 |
Correct |
12 ms |
23764 KB |
Output is correct |
9 |
Correct |
12 ms |
23788 KB |
Output is correct |
10 |
Correct |
13 ms |
23796 KB |
Output is correct |
11 |
Correct |
12 ms |
23764 KB |
Output is correct |
12 |
Correct |
13 ms |
23672 KB |
Output is correct |
13 |
Correct |
13 ms |
23764 KB |
Output is correct |
14 |
Correct |
12 ms |
23764 KB |
Output is correct |
15 |
Correct |
12 ms |
23700 KB |
Output is correct |
16 |
Correct |
12 ms |
23796 KB |
Output is correct |
17 |
Correct |
13 ms |
23764 KB |
Output is correct |
18 |
Correct |
13 ms |
23764 KB |
Output is correct |
19 |
Correct |
15 ms |
23792 KB |
Output is correct |
20 |
Correct |
13 ms |
23764 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
12 ms |
23764 KB |
Output is correct |
2 |
Correct |
11 ms |
23696 KB |
Output is correct |
3 |
Correct |
11 ms |
23764 KB |
Output is correct |
4 |
Correct |
13 ms |
23728 KB |
Output is correct |
5 |
Correct |
12 ms |
23764 KB |
Output is correct |
6 |
Correct |
12 ms |
23764 KB |
Output is correct |
7 |
Correct |
11 ms |
23764 KB |
Output is correct |
8 |
Correct |
12 ms |
23764 KB |
Output is correct |
9 |
Correct |
12 ms |
23788 KB |
Output is correct |
10 |
Correct |
13 ms |
23796 KB |
Output is correct |
11 |
Correct |
12 ms |
23764 KB |
Output is correct |
12 |
Correct |
13 ms |
23672 KB |
Output is correct |
13 |
Correct |
13 ms |
23764 KB |
Output is correct |
14 |
Correct |
12 ms |
23764 KB |
Output is correct |
15 |
Correct |
12 ms |
23700 KB |
Output is correct |
16 |
Correct |
12 ms |
23796 KB |
Output is correct |
17 |
Correct |
13 ms |
23764 KB |
Output is correct |
18 |
Correct |
13 ms |
23764 KB |
Output is correct |
19 |
Correct |
15 ms |
23792 KB |
Output is correct |
20 |
Correct |
13 ms |
23764 KB |
Output is correct |
21 |
Correct |
13 ms |
23792 KB |
Output is correct |
22 |
Correct |
15 ms |
23924 KB |
Output is correct |
23 |
Correct |
14 ms |
23892 KB |
Output is correct |
24 |
Correct |
15 ms |
23908 KB |
Output is correct |
25 |
Correct |
15 ms |
23908 KB |
Output is correct |
26 |
Correct |
15 ms |
23892 KB |
Output is correct |
27 |
Correct |
14 ms |
23848 KB |
Output is correct |
28 |
Correct |
14 ms |
23800 KB |
Output is correct |
29 |
Correct |
14 ms |
23792 KB |
Output is correct |
30 |
Correct |
14 ms |
23688 KB |
Output is correct |
31 |
Correct |
14 ms |
23892 KB |
Output is correct |
32 |
Correct |
13 ms |
23764 KB |
Output is correct |
33 |
Correct |
12 ms |
23788 KB |
Output is correct |
34 |
Correct |
12 ms |
23764 KB |
Output is correct |
35 |
Correct |
13 ms |
23708 KB |
Output is correct |
36 |
Correct |
12 ms |
23792 KB |
Output is correct |
37 |
Correct |
13 ms |
23764 KB |
Output is correct |
38 |
Correct |
12 ms |
23796 KB |
Output is correct |
39 |
Correct |
12 ms |
23764 KB |
Output is correct |
40 |
Correct |
12 ms |
23764 KB |
Output is correct |
41 |
Correct |
14 ms |
23764 KB |
Output is correct |
42 |
Correct |
12 ms |
23792 KB |
Output is correct |
43 |
Correct |
12 ms |
23792 KB |
Output is correct |
44 |
Correct |
12 ms |
23764 KB |
Output is correct |
45 |
Correct |
12 ms |
23764 KB |
Output is correct |
46 |
Correct |
15 ms |
23796 KB |
Output is correct |
47 |
Correct |
12 ms |
23756 KB |
Output is correct |
48 |
Correct |
13 ms |
23764 KB |
Output is correct |
49 |
Correct |
13 ms |
23764 KB |
Output is correct |
50 |
Correct |
12 ms |
23764 KB |
Output is correct |
51 |
Correct |
13 ms |
23764 KB |
Output is correct |
52 |
Correct |
12 ms |
23792 KB |
Output is correct |
53 |
Correct |
13 ms |
23732 KB |
Output is correct |
54 |
Correct |
12 ms |
23764 KB |
Output is correct |
55 |
Correct |
13 ms |
23764 KB |
Output is correct |
56 |
Correct |
13 ms |
23704 KB |
Output is correct |
57 |
Correct |
13 ms |
23764 KB |
Output is correct |
58 |
Correct |
14 ms |
23880 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
12 ms |
23764 KB |
Output is correct |
2 |
Correct |
11 ms |
23696 KB |
Output is correct |
3 |
Correct |
11 ms |
23764 KB |
Output is correct |
4 |
Correct |
13 ms |
23728 KB |
Output is correct |
5 |
Correct |
12 ms |
23764 KB |
Output is correct |
6 |
Correct |
12 ms |
23764 KB |
Output is correct |
7 |
Correct |
11 ms |
23764 KB |
Output is correct |
8 |
Correct |
12 ms |
23764 KB |
Output is correct |
9 |
Correct |
12 ms |
23788 KB |
Output is correct |
10 |
Correct |
13 ms |
23796 KB |
Output is correct |
11 |
Correct |
12 ms |
23764 KB |
Output is correct |
12 |
Correct |
13 ms |
23672 KB |
Output is correct |
13 |
Correct |
13 ms |
23764 KB |
Output is correct |
14 |
Correct |
12 ms |
23764 KB |
Output is correct |
15 |
Correct |
12 ms |
23700 KB |
Output is correct |
16 |
Correct |
12 ms |
23796 KB |
Output is correct |
17 |
Correct |
13 ms |
23764 KB |
Output is correct |
18 |
Correct |
13 ms |
23764 KB |
Output is correct |
19 |
Correct |
15 ms |
23792 KB |
Output is correct |
20 |
Correct |
13 ms |
23764 KB |
Output is correct |
21 |
Correct |
13 ms |
23792 KB |
Output is correct |
22 |
Correct |
15 ms |
23924 KB |
Output is correct |
23 |
Correct |
14 ms |
23892 KB |
Output is correct |
24 |
Correct |
15 ms |
23908 KB |
Output is correct |
25 |
Correct |
15 ms |
23908 KB |
Output is correct |
26 |
Correct |
15 ms |
23892 KB |
Output is correct |
27 |
Correct |
14 ms |
23848 KB |
Output is correct |
28 |
Correct |
14 ms |
23800 KB |
Output is correct |
29 |
Correct |
14 ms |
23792 KB |
Output is correct |
30 |
Correct |
14 ms |
23688 KB |
Output is correct |
31 |
Correct |
14 ms |
23892 KB |
Output is correct |
32 |
Correct |
13 ms |
23764 KB |
Output is correct |
33 |
Correct |
12 ms |
23788 KB |
Output is correct |
34 |
Correct |
12 ms |
23764 KB |
Output is correct |
35 |
Correct |
13 ms |
23708 KB |
Output is correct |
36 |
Correct |
12 ms |
23792 KB |
Output is correct |
37 |
Correct |
13 ms |
23764 KB |
Output is correct |
38 |
Correct |
12 ms |
23796 KB |
Output is correct |
39 |
Correct |
12 ms |
23764 KB |
Output is correct |
40 |
Correct |
12 ms |
23764 KB |
Output is correct |
41 |
Correct |
14 ms |
23764 KB |
Output is correct |
42 |
Correct |
12 ms |
23792 KB |
Output is correct |
43 |
Correct |
12 ms |
23792 KB |
Output is correct |
44 |
Correct |
12 ms |
23764 KB |
Output is correct |
45 |
Correct |
12 ms |
23764 KB |
Output is correct |
46 |
Correct |
15 ms |
23796 KB |
Output is correct |
47 |
Correct |
12 ms |
23756 KB |
Output is correct |
48 |
Correct |
13 ms |
23764 KB |
Output is correct |
49 |
Correct |
13 ms |
23764 KB |
Output is correct |
50 |
Correct |
12 ms |
23764 KB |
Output is correct |
51 |
Correct |
13 ms |
23764 KB |
Output is correct |
52 |
Correct |
12 ms |
23792 KB |
Output is correct |
53 |
Correct |
13 ms |
23732 KB |
Output is correct |
54 |
Correct |
12 ms |
23764 KB |
Output is correct |
55 |
Correct |
13 ms |
23764 KB |
Output is correct |
56 |
Correct |
13 ms |
23704 KB |
Output is correct |
57 |
Correct |
13 ms |
23764 KB |
Output is correct |
58 |
Correct |
14 ms |
23880 KB |
Output is correct |
59 |
Correct |
582 ms |
50572 KB |
Output is correct |
60 |
Correct |
652 ms |
49604 KB |
Output is correct |
61 |
Correct |
13 ms |
23712 KB |
Output is correct |
62 |
Correct |
13 ms |
23764 KB |
Output is correct |
63 |
Correct |
498 ms |
46672 KB |
Output is correct |
64 |
Correct |
15 ms |
24296 KB |
Output is correct |
65 |
Correct |
31 ms |
25996 KB |
Output is correct |
66 |
Correct |
226 ms |
42304 KB |
Output is correct |
67 |
Correct |
751 ms |
60424 KB |
Output is correct |
68 |
Correct |
734 ms |
61532 KB |
Output is correct |
69 |
Correct |
24 ms |
25228 KB |
Output is correct |
70 |
Correct |
156 ms |
37280 KB |
Output is correct |
71 |
Correct |
556 ms |
66616 KB |
Output is correct |
72 |
Correct |
644 ms |
64112 KB |
Output is correct |
73 |
Correct |
135 ms |
31504 KB |
Output is correct |
74 |
Correct |
668 ms |
47972 KB |
Output is correct |
75 |
Correct |
55 ms |
28040 KB |
Output is correct |
76 |
Correct |
521 ms |
59060 KB |
Output is correct |
77 |
Correct |
525 ms |
59776 KB |
Output is correct |
78 |
Correct |
61 ms |
27544 KB |
Output is correct |
79 |
Correct |
761 ms |
58456 KB |
Output is correct |
80 |
Correct |
15 ms |
24020 KB |
Output is correct |
81 |
Correct |
205 ms |
35924 KB |
Output is correct |
82 |
Correct |
604 ms |
57404 KB |
Output is correct |
83 |
Correct |
655 ms |
48284 KB |
Output is correct |
84 |
Correct |
648 ms |
48508 KB |
Output is correct |
85 |
Correct |
656 ms |
48664 KB |
Output is correct |
86 |
Correct |
641 ms |
49584 KB |
Output is correct |
87 |
Correct |
655 ms |
49684 KB |
Output is correct |