# |
Submission time |
Handle |
Problem |
Language |
Result |
Execution time |
Memory |
137092 |
2019-07-27T05:12:57 Z |
silxikys |
Network (BOI15_net) |
C++14 |
|
1022 ms |
62668 KB |
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int maxn = 5e5+5;
int n;
int deg[maxn];
int subtree[maxn];
int pre[maxn];
int low[maxn];
bool v[maxn];
int point = 0;
struct Edge
{
int to, id;
};
vector<Edge> adj[maxn];
bool hasBridge = false;
void go(int now, int fromID) {
if (hasBridge) return;
pre[now] = point++;
v[now] = true;
low[now] = pre[now];
bool isArt = false;
int childCnt = 0;
for (int i = 0; i < adj[now].size(); i++) {
if (adj[now][i].id == fromID) continue;
int to = adj[now][i].to;
if (v[to]) {
//to must be an ancestor of now
low[now] = min(low[now],pre[to]);
}
else {
//bold edge going downwards
go(to,adj[now][i].id);
childCnt++;
low[now] = min(low[now],low[to]);
if (low[to] >= pre[now]) {
isArt = true;
}
if (pre[now] < low[to]) {
hasBridge = true;
}
}
}
if (fromID == -1) {
isArt = childCnt != 1;
}
}
int main()
{
ios_base::sync_with_stdio(false); cin.tie(NULL);
srand(time(NULL));
cin >> n;
vector<pair<int,int>> edges;
for (int i = 0; i < n - 1; i++) {
int a, b; cin >> a >> b;
++deg[a];
++deg[b];
edges.push_back({a,b});
}
vector<int> leafs;
for (int i = 1; i <= n; i++) {
if (deg[i] == 1) leafs.push_back(i);
}
while (true) {
point = 0;
memset(v,false,sizeof v);
memset(pre,0,sizeof pre);
memset(low,false,sizeof low);
hasBridge = false;
random_shuffle(leafs.begin(),leafs.end());
int id = 0;
for (int i = 1; i <= n; i++) {
adj[i].clear();
}
for (int i = 0; i < n - 1; i++, id++) {
adj[edges[i].second].push_back({edges[i].first,id});
adj[edges[i].first].push_back({edges[i].second,id});
}
for (int i = 0; i < leafs.size(); i += 2, id++) {
int nxt = leafs[(i+1)%leafs.size()];
adj[leafs[i]].push_back({nxt,id});
adj[nxt].push_back({leafs[i],id});
}
go(1,-1);
if (!hasBridge) {
//output
cout << ((leafs.size()+1)/2) << '\n';
for (int i = 0; i < leafs.size(); i += 2, id++) {
int nxt = leafs[(i+1)%leafs.size()];
cout << leafs[i] << ' ' << nxt << '\n';
}
return 0;
}
}
}
Compilation message
net.cpp: In function 'void go(int, int)':
net.cpp:31:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < adj[now].size(); i++) {
~~^~~~~~~~~~~~~~~~~
net.cpp:29:10: warning: variable 'isArt' set but not used [-Wunused-but-set-variable]
bool isArt = false;
^~~~~
net.cpp: In function 'int main()':
net.cpp:87:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < leafs.size(); i += 2, id++) {
~~^~~~~~~~~~~~~~
net.cpp:96:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < leafs.size(); i += 2, id++) {
~~^~~~~~~~~~~~~~
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
17 ms |
16504 KB |
Output is correct |
2 |
Correct |
17 ms |
16504 KB |
Output is correct |
3 |
Correct |
17 ms |
16504 KB |
Output is correct |
4 |
Correct |
17 ms |
16504 KB |
Output is correct |
5 |
Correct |
16 ms |
16504 KB |
Output is correct |
6 |
Correct |
20 ms |
16504 KB |
Output is correct |
7 |
Correct |
20 ms |
16504 KB |
Output is correct |
8 |
Correct |
21 ms |
16504 KB |
Output is correct |
9 |
Correct |
20 ms |
16504 KB |
Output is correct |
10 |
Correct |
21 ms |
16508 KB |
Output is correct |
11 |
Correct |
20 ms |
16632 KB |
Output is correct |
12 |
Correct |
16 ms |
16504 KB |
Output is correct |
13 |
Correct |
19 ms |
16504 KB |
Output is correct |
14 |
Correct |
21 ms |
16504 KB |
Output is correct |
15 |
Correct |
19 ms |
16504 KB |
Output is correct |
16 |
Correct |
16 ms |
16504 KB |
Output is correct |
17 |
Correct |
17 ms |
16504 KB |
Output is correct |
18 |
Correct |
17 ms |
16504 KB |
Output is correct |
19 |
Correct |
17 ms |
16504 KB |
Output is correct |
20 |
Correct |
17 ms |
16504 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
17 ms |
16504 KB |
Output is correct |
2 |
Correct |
17 ms |
16504 KB |
Output is correct |
3 |
Correct |
17 ms |
16504 KB |
Output is correct |
4 |
Correct |
17 ms |
16504 KB |
Output is correct |
5 |
Correct |
16 ms |
16504 KB |
Output is correct |
6 |
Correct |
20 ms |
16504 KB |
Output is correct |
7 |
Correct |
20 ms |
16504 KB |
Output is correct |
8 |
Correct |
21 ms |
16504 KB |
Output is correct |
9 |
Correct |
20 ms |
16504 KB |
Output is correct |
10 |
Correct |
21 ms |
16508 KB |
Output is correct |
11 |
Correct |
20 ms |
16632 KB |
Output is correct |
12 |
Correct |
16 ms |
16504 KB |
Output is correct |
13 |
Correct |
19 ms |
16504 KB |
Output is correct |
14 |
Correct |
21 ms |
16504 KB |
Output is correct |
15 |
Correct |
19 ms |
16504 KB |
Output is correct |
16 |
Correct |
16 ms |
16504 KB |
Output is correct |
17 |
Correct |
17 ms |
16504 KB |
Output is correct |
18 |
Correct |
17 ms |
16504 KB |
Output is correct |
19 |
Correct |
17 ms |
16504 KB |
Output is correct |
20 |
Correct |
17 ms |
16504 KB |
Output is correct |
21 |
Correct |
17 ms |
16504 KB |
Output is correct |
22 |
Correct |
18 ms |
16632 KB |
Output is correct |
23 |
Correct |
17 ms |
16604 KB |
Output is correct |
24 |
Correct |
18 ms |
16632 KB |
Output is correct |
25 |
Correct |
20 ms |
16760 KB |
Output is correct |
26 |
Correct |
17 ms |
16644 KB |
Output is correct |
27 |
Correct |
22 ms |
16760 KB |
Output is correct |
28 |
Correct |
17 ms |
16760 KB |
Output is correct |
29 |
Correct |
17 ms |
16732 KB |
Output is correct |
30 |
Correct |
17 ms |
16484 KB |
Output is correct |
31 |
Correct |
19 ms |
16760 KB |
Output is correct |
32 |
Correct |
17 ms |
16504 KB |
Output is correct |
33 |
Correct |
20 ms |
16504 KB |
Output is correct |
34 |
Correct |
17 ms |
16508 KB |
Output is correct |
35 |
Correct |
17 ms |
16504 KB |
Output is correct |
36 |
Correct |
17 ms |
16508 KB |
Output is correct |
37 |
Correct |
17 ms |
16632 KB |
Output is correct |
38 |
Correct |
18 ms |
16632 KB |
Output is correct |
39 |
Correct |
16 ms |
16504 KB |
Output is correct |
40 |
Correct |
16 ms |
16504 KB |
Output is correct |
41 |
Correct |
16 ms |
16476 KB |
Output is correct |
42 |
Correct |
17 ms |
16504 KB |
Output is correct |
43 |
Correct |
17 ms |
16512 KB |
Output is correct |
44 |
Correct |
17 ms |
16504 KB |
Output is correct |
45 |
Correct |
17 ms |
16504 KB |
Output is correct |
46 |
Correct |
18 ms |
16632 KB |
Output is correct |
47 |
Correct |
17 ms |
16532 KB |
Output is correct |
48 |
Correct |
17 ms |
16508 KB |
Output is correct |
49 |
Correct |
17 ms |
16632 KB |
Output is correct |
50 |
Correct |
17 ms |
16504 KB |
Output is correct |
51 |
Correct |
17 ms |
16504 KB |
Output is correct |
52 |
Correct |
17 ms |
16504 KB |
Output is correct |
53 |
Correct |
17 ms |
16504 KB |
Output is correct |
54 |
Correct |
17 ms |
16504 KB |
Output is correct |
55 |
Correct |
29 ms |
16504 KB |
Output is correct |
56 |
Correct |
17 ms |
16504 KB |
Output is correct |
57 |
Correct |
17 ms |
16504 KB |
Output is correct |
58 |
Correct |
18 ms |
16632 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
17 ms |
16504 KB |
Output is correct |
2 |
Correct |
17 ms |
16504 KB |
Output is correct |
3 |
Correct |
17 ms |
16504 KB |
Output is correct |
4 |
Correct |
17 ms |
16504 KB |
Output is correct |
5 |
Correct |
16 ms |
16504 KB |
Output is correct |
6 |
Correct |
20 ms |
16504 KB |
Output is correct |
7 |
Correct |
20 ms |
16504 KB |
Output is correct |
8 |
Correct |
21 ms |
16504 KB |
Output is correct |
9 |
Correct |
20 ms |
16504 KB |
Output is correct |
10 |
Correct |
21 ms |
16508 KB |
Output is correct |
11 |
Correct |
20 ms |
16632 KB |
Output is correct |
12 |
Correct |
16 ms |
16504 KB |
Output is correct |
13 |
Correct |
19 ms |
16504 KB |
Output is correct |
14 |
Correct |
21 ms |
16504 KB |
Output is correct |
15 |
Correct |
19 ms |
16504 KB |
Output is correct |
16 |
Correct |
16 ms |
16504 KB |
Output is correct |
17 |
Correct |
17 ms |
16504 KB |
Output is correct |
18 |
Correct |
17 ms |
16504 KB |
Output is correct |
19 |
Correct |
17 ms |
16504 KB |
Output is correct |
20 |
Correct |
17 ms |
16504 KB |
Output is correct |
21 |
Correct |
17 ms |
16504 KB |
Output is correct |
22 |
Correct |
18 ms |
16632 KB |
Output is correct |
23 |
Correct |
17 ms |
16604 KB |
Output is correct |
24 |
Correct |
18 ms |
16632 KB |
Output is correct |
25 |
Correct |
20 ms |
16760 KB |
Output is correct |
26 |
Correct |
17 ms |
16644 KB |
Output is correct |
27 |
Correct |
22 ms |
16760 KB |
Output is correct |
28 |
Correct |
17 ms |
16760 KB |
Output is correct |
29 |
Correct |
17 ms |
16732 KB |
Output is correct |
30 |
Correct |
17 ms |
16484 KB |
Output is correct |
31 |
Correct |
19 ms |
16760 KB |
Output is correct |
32 |
Correct |
17 ms |
16504 KB |
Output is correct |
33 |
Correct |
20 ms |
16504 KB |
Output is correct |
34 |
Correct |
17 ms |
16508 KB |
Output is correct |
35 |
Correct |
17 ms |
16504 KB |
Output is correct |
36 |
Correct |
17 ms |
16508 KB |
Output is correct |
37 |
Correct |
17 ms |
16632 KB |
Output is correct |
38 |
Correct |
18 ms |
16632 KB |
Output is correct |
39 |
Correct |
16 ms |
16504 KB |
Output is correct |
40 |
Correct |
16 ms |
16504 KB |
Output is correct |
41 |
Correct |
16 ms |
16476 KB |
Output is correct |
42 |
Correct |
17 ms |
16504 KB |
Output is correct |
43 |
Correct |
17 ms |
16512 KB |
Output is correct |
44 |
Correct |
17 ms |
16504 KB |
Output is correct |
45 |
Correct |
17 ms |
16504 KB |
Output is correct |
46 |
Correct |
18 ms |
16632 KB |
Output is correct |
47 |
Correct |
17 ms |
16532 KB |
Output is correct |
48 |
Correct |
17 ms |
16508 KB |
Output is correct |
49 |
Correct |
17 ms |
16632 KB |
Output is correct |
50 |
Correct |
17 ms |
16504 KB |
Output is correct |
51 |
Correct |
17 ms |
16504 KB |
Output is correct |
52 |
Correct |
17 ms |
16504 KB |
Output is correct |
53 |
Correct |
17 ms |
16504 KB |
Output is correct |
54 |
Correct |
17 ms |
16504 KB |
Output is correct |
55 |
Correct |
29 ms |
16504 KB |
Output is correct |
56 |
Correct |
17 ms |
16504 KB |
Output is correct |
57 |
Correct |
17 ms |
16504 KB |
Output is correct |
58 |
Correct |
18 ms |
16632 KB |
Output is correct |
59 |
Correct |
941 ms |
60240 KB |
Output is correct |
60 |
Correct |
736 ms |
58368 KB |
Output is correct |
61 |
Correct |
17 ms |
16504 KB |
Output is correct |
62 |
Correct |
17 ms |
16504 KB |
Output is correct |
63 |
Correct |
587 ms |
51048 KB |
Output is correct |
64 |
Correct |
19 ms |
16888 KB |
Output is correct |
65 |
Correct |
30 ms |
18424 KB |
Output is correct |
66 |
Correct |
215 ms |
30308 KB |
Output is correct |
67 |
Correct |
618 ms |
62668 KB |
Output is correct |
68 |
Correct |
624 ms |
52320 KB |
Output is correct |
69 |
Correct |
26 ms |
17656 KB |
Output is correct |
70 |
Correct |
150 ms |
27752 KB |
Output is correct |
71 |
Correct |
591 ms |
48316 KB |
Output is correct |
72 |
Correct |
639 ms |
47452 KB |
Output is correct |
73 |
Correct |
139 ms |
28136 KB |
Output is correct |
74 |
Correct |
689 ms |
55388 KB |
Output is correct |
75 |
Correct |
52 ms |
20468 KB |
Output is correct |
76 |
Correct |
633 ms |
53660 KB |
Output is correct |
77 |
Correct |
652 ms |
47300 KB |
Output is correct |
78 |
Correct |
50 ms |
20596 KB |
Output is correct |
79 |
Correct |
616 ms |
56672 KB |
Output is correct |
80 |
Correct |
19 ms |
16760 KB |
Output is correct |
81 |
Correct |
175 ms |
27112 KB |
Output is correct |
82 |
Correct |
659 ms |
48120 KB |
Output is correct |
83 |
Correct |
679 ms |
54368 KB |
Output is correct |
84 |
Correct |
1022 ms |
54392 KB |
Output is correct |
85 |
Correct |
700 ms |
54436 KB |
Output is correct |
86 |
Correct |
704 ms |
57180 KB |
Output is correct |
87 |
Correct |
713 ms |
57316 KB |
Output is correct |