# | Submission time | Handle | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
605817 | 2022-07-26T02:43:25 Z | buidangnguyen05 | Network (BOI15_net) | C++14 | 16 ms | 24224 KB |
//source: https://oj.uz/problem/view/BOI15_net #include<bits/stdc++.h> using namespace std; typedef long long ll; const int N = 5e5 + 10; vector<int> adj[N]; vector<pair<int, int>> ans; vector<int> dfs(int x, int par) { if (adj[x].size() == 1) return vector<int>(1, x); vector<int> cur; for (int i : adj[x]) if (i != par) { vector<int> v = dfs(i, x); if (cur.size() < v.size()) swap(v, cur); while (cur.size() + v.size() > (!par ? 0 : 2) && v.size()) { int p = cur.back(); cur.pop_back(); int q = v.back(); v.pop_back(); ans.emplace_back(p, q); } for (int j : v) cur.push_back(j); } return cur; } signed main() { cin.tie(0)->sync_with_stdio(0); if (fopen("task.inp", "r")) { freopen("task.inp", "r", stdin); freopen("task.out", "w", stdout); } int n; cin >> n; for (int i = 1; i < n; ++i) { int x, y; cin >> x >> y; adj[x].push_back(y); adj[y].push_back(x); } int root = 0, save1 = 0, save2 = 0; for (int i = 1; i <= n; ++i) { if (adj[i].size() > 1) root = i; else if (!save1) save1 = i; else save2 = i; } vector<int> rem = dfs(root, 0); assert(rem.size() < 2); if (rem.size()) ans.emplace_back(rem.back(), (save1 == rem.back() ? save2 : save1)); cout << ans.size() << "\n"; for (pair<int, int> i : ans) cout << i.first << " " << i.second << "\n"; }
Compilation message
# | Verdict | Execution time | Memory | Grader output |
---|---|---|---|---|
1 | Correct | 6 ms | 12060 KB | Output is correct |
2 | Correct | 6 ms | 11988 KB | Output is correct |
3 | Correct | 6 ms | 11988 KB | Output is correct |
4 | Correct | 6 ms | 12040 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 | 6 ms | 11988 KB | Output is correct |
10 | Correct | 6 ms | 11988 KB | Output is correct |
11 | Correct | 6 ms | 12012 KB | Output is correct |
12 | Correct | 7 ms | 11988 KB | Output is correct |
13 | Correct | 7 ms | 11988 KB | Output is correct |
14 | Runtime error | 16 ms | 24224 KB | Execution killed with signal 6 |
15 | Halted | 0 ms | 0 KB | - |
# | Verdict | Execution time | Memory | Grader output |
---|---|---|---|---|
1 | Correct | 6 ms | 12060 KB | Output is correct |
2 | Correct | 6 ms | 11988 KB | Output is correct |
3 | Correct | 6 ms | 11988 KB | Output is correct |
4 | Correct | 6 ms | 12040 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 | 6 ms | 11988 KB | Output is correct |
10 | Correct | 6 ms | 11988 KB | Output is correct |
11 | Correct | 6 ms | 12012 KB | Output is correct |
12 | Correct | 7 ms | 11988 KB | Output is correct |
13 | Correct | 7 ms | 11988 KB | Output is correct |
14 | Runtime error | 16 ms | 24224 KB | Execution killed with signal 6 |
15 | Halted | 0 ms | 0 KB | - |
# | Verdict | Execution time | Memory | Grader output |
---|---|---|---|---|
1 | Correct | 6 ms | 12060 KB | Output is correct |
2 | Correct | 6 ms | 11988 KB | Output is correct |
3 | Correct | 6 ms | 11988 KB | Output is correct |
4 | Correct | 6 ms | 12040 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 | 6 ms | 11988 KB | Output is correct |
10 | Correct | 6 ms | 11988 KB | Output is correct |
11 | Correct | 6 ms | 12012 KB | Output is correct |
12 | Correct | 7 ms | 11988 KB | Output is correct |
13 | Correct | 7 ms | 11988 KB | Output is correct |
14 | Runtime error | 16 ms | 24224 KB | Execution killed with signal 6 |
15 | Halted | 0 ms | 0 KB | - |