oj.uz

Submission #606591

# Submission time Handle Problem Language Result Execution time Memory
606591 2022-07-26T07:19:16 Z nguyentunglam Network (BOI15_net) C++14
100 / 100
 498 ms 68212 KB 
#include<bits/stdc++.h>
#define forin(i, a, b) for(int i = a; i <= b; i++)
#define forde(i, a, b) for(int i = a; i >= b; i--)
#define forv(a, b) for(auto & a : b)
#define fi first
#define se second
using namespace std;
const int N = 5e5 + 10;
int n;
vector<int> adj[N];
vector<pair<int, int>> ans;
vector<int> dfs(int u, int par) {
    vector<int> f;
    if (adj[u].size() == 1) {
        f.push_back(u);
        return f;
    }
    forv(v, adj[u]) if (v != par) {
        vector<int> g = dfs(v, u);
        if (f.size() < g.size()) swap(f, g);
        while (f.size() + g.size() > 2) {
            ans.push_back({f.back(), g.back()});
            f.pop_back(); g.pop_back();
        }
        forv(t, g) f.push_back(t);
    }
    return f;
}
int main() {
    cin.tie(0) -> sync_with_stdio(0);
    if (fopen ("task.inp", "r")) {
        freopen ("task.inp", "r", stdin);
        freopen ("task.out", "w", stdout);
    }
    if (fopen ("bluehouse.inp", "r")) {
        freopen ("bluehouse.inp", "r", stdin);
        freopen ("bluehouse.out", "w", stdout);
    }
    cin >> n;
    forin(i, 1, n - 1) {
        int a, b; cin >> a >> b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    forin(i, 1, n) if (adj[i].size() > 1) {
        vector<int> t = dfs(i, 0);
        if (t.size() >= 2) {
            int u = t.back(); t.pop_back();
            int v = t.back(); t.pop_back();
            ans.push_back({u, v});
        }
        if (!t.empty()) ans.push_back({i, t[0]});
        break;
    }
    cout << ans.size() << "\n";
    forv(v, ans) cout << v.fi << " " << v.se << "\n";
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:32:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |         freopen ("task.inp", "r", stdin);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
net.cpp:33:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |         freopen ("task.out", "w", stdout);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
net.cpp:36:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |         freopen ("bluehouse.inp", "r", stdin);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
net.cpp:37:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen ("bluehouse.out", "w", stdout);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11988 KB Output is correct
2 Correct 7 ms 12068 KB Output is correct
3 Correct 6 ms 12072 KB Output is correct
4 Correct 8 ms 12064 KB Output is correct
5 Correct 6 ms 11988 KB Output is correct
6 Correct 6 ms 11988 KB Output is correct
7 Correct 7 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 12068 KB Output is correct
11 Correct 7 ms 12044 KB Output is correct
12 Correct 6 ms 11988 KB Output is correct
13 Correct 8 ms 12076 KB Output is correct
14 Correct 7 ms 11988 KB Output is correct
15 Correct 7 ms 12064 KB Output is correct
16 Correct 7 ms 12068 KB Output is correct
17 Correct 7 ms 11988 KB Output is correct
18 Correct 8 ms 11988 KB Output is correct
19 Correct 7 ms 11988 KB Output is correct
20 Correct 6 ms 11988 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11988 KB Output is correct
2 Correct 7 ms 12068 KB Output is correct
3 Correct 6 ms 12072 KB Output is correct
4 Correct 8 ms 12064 KB Output is correct
5 Correct 6 ms 11988 KB Output is correct
6 Correct 6 ms 11988 KB Output is correct
7 Correct 7 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 12068 KB Output is correct
11 Correct 7 ms 12044 KB Output is correct
12 Correct 6 ms 11988 KB Output is correct
13 Correct 8 ms 12076 KB Output is correct
14 Correct 7 ms 11988 KB Output is correct
15 Correct 7 ms 12064 KB Output is correct
16 Correct 7 ms 12068 KB Output is correct
17 Correct 7 ms 11988 KB Output is correct
18 Correct 8 ms 11988 KB Output is correct
19 Correct 7 ms 11988 KB Output is correct
20 Correct 6 ms 11988 KB Output is correct
21 Correct 7 ms 12068 KB Output is correct
22 Correct 8 ms 12092 KB Output is correct
23 Correct 7 ms 12116 KB Output is correct
24 Correct 7 ms 12116 KB Output is correct
25 Correct 8 ms 12116 KB Output is correct
26 Correct 7 ms 12116 KB Output is correct
27 Correct 9 ms 12116 KB Output is correct
28 Correct 9 ms 12116 KB Output is correct
29 Correct 8 ms 12116 KB Output is correct
30 Correct 7 ms 12064 KB Output is correct
31 Correct 7 ms 12116 KB Output is correct
32 Correct 7 ms 12064 KB Output is correct
33 Correct 6 ms 12072 KB Output is correct
34 Correct 6 ms 11988 KB Output is correct
35 Correct 6 ms 11944 KB Output is correct
36 Correct 6 ms 12012 KB Output is correct
37 Correct 7 ms 12068 KB Output is correct
38 Correct 8 ms 12116 KB Output is correct
39 Correct 8 ms 11988 KB Output is correct
40 Correct 8 ms 12068 KB Output is correct
41 Correct 8 ms 11988 KB Output is correct
42 Correct 7 ms 12068 KB Output is correct
43 Correct 9 ms 12160 KB Output is correct
44 Correct 7 ms 11988 KB Output is correct
45 Correct 9 ms 12048 KB Output is correct
46 Correct 7 ms 11988 KB Output is correct
47 Correct 7 ms 12056 KB Output is correct
48 Correct 7 ms 11988 KB Output is correct
49 Correct 7 ms 12104 KB Output is correct
50 Correct 6 ms 11988 KB Output is correct
51 Correct 8 ms 12104 KB Output is correct
52 Correct 7 ms 12064 KB Output is correct
53 Correct 8 ms 12116 KB Output is correct
54 Correct 6 ms 11988 KB Output is correct
55 Correct 9 ms 11988 KB Output is correct
56 Correct 9 ms 11988 KB Output is correct
57 Correct 7 ms 11988 KB Output is correct
58 Correct 7 ms 12116 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11988 KB Output is correct
2 Correct 7 ms 12068 KB Output is correct
3 Correct 6 ms 12072 KB Output is correct
4 Correct 8 ms 12064 KB Output is correct
5 Correct 6 ms 11988 KB Output is correct
6 Correct 6 ms 11988 KB Output is correct
7 Correct 7 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 12068 KB Output is correct
11 Correct 7 ms 12044 KB Output is correct
12 Correct 6 ms 11988 KB Output is correct
13 Correct 8 ms 12076 KB Output is correct
14 Correct 7 ms 11988 KB Output is correct
15 Correct 7 ms 12064 KB Output is correct
16 Correct 7 ms 12068 KB Output is correct
17 Correct 7 ms 11988 KB Output is correct
18 Correct 8 ms 11988 KB Output is correct
19 Correct 7 ms 11988 KB Output is correct
20 Correct 6 ms 11988 KB Output is correct
21 Correct 7 ms 12068 KB Output is correct
22 Correct 8 ms 12092 KB Output is correct
23 Correct 7 ms 12116 KB Output is correct
24 Correct 7 ms 12116 KB Output is correct
25 Correct 8 ms 12116 KB Output is correct
26 Correct 7 ms 12116 KB Output is correct
27 Correct 9 ms 12116 KB Output is correct
28 Correct 9 ms 12116 KB Output is correct
29 Correct 8 ms 12116 KB Output is correct
30 Correct 7 ms 12064 KB Output is correct
31 Correct 7 ms 12116 KB Output is correct
32 Correct 7 ms 12064 KB Output is correct
33 Correct 6 ms 12072 KB Output is correct
34 Correct 6 ms 11988 KB Output is correct
35 Correct 6 ms 11944 KB Output is correct
36 Correct 6 ms 12012 KB Output is correct
37 Correct 7 ms 12068 KB Output is correct
38 Correct 8 ms 12116 KB Output is correct
39 Correct 8 ms 11988 KB Output is correct
40 Correct 8 ms 12068 KB Output is correct
41 Correct 8 ms 11988 KB Output is correct
42 Correct 7 ms 12068 KB Output is correct
43 Correct 9 ms 12160 KB Output is correct
44 Correct 7 ms 11988 KB Output is correct
45 Correct 9 ms 12048 KB Output is correct
46 Correct 7 ms 11988 KB Output is correct
47 Correct 7 ms 12056 KB Output is correct
48 Correct 7 ms 11988 KB Output is correct
49 Correct 7 ms 12104 KB Output is correct
50 Correct 6 ms 11988 KB Output is correct
51 Correct 8 ms 12104 KB Output is correct
52 Correct 7 ms 12064 KB Output is correct
53 Correct 8 ms 12116 KB Output is correct
54 Correct 6 ms 11988 KB Output is correct
55 Correct 9 ms 11988 KB Output is correct
56 Correct 9 ms 11988 KB Output is correct
57 Correct 7 ms 11988 KB Output is correct
58 Correct 7 ms 12116 KB Output is correct
59 Correct 311 ms 31276 KB Output is correct
60 Correct 415 ms 33340 KB Output is correct
61 Correct 7 ms 11988 KB Output is correct
62 Correct 6 ms 11988 KB Output is correct
63 Correct 328 ms 29548 KB Output is correct
64 Correct 9 ms 12852 KB Output is correct
65 Correct 17 ms 15580 KB Output is correct
66 Correct 130 ms 42840 KB Output is correct
67 Correct 458 ms 66752 KB Output is correct
68 Correct 498 ms 68212 KB Output is correct
69 Correct 14 ms 12884 KB Output is correct
70 Correct 81 ms 20452 KB Output is correct
71 Correct 312 ms 36364 KB Output is correct
72 Correct 310 ms 35640 KB Output is correct
73 Correct 106 ms 18636 KB Output is correct
74 Correct 416 ms 32408 KB Output is correct
75 Correct 34 ms 15172 KB Output is correct
76 Correct 318 ms 36152 KB Output is correct
77 Correct 392 ms 36380 KB Output is correct
78 Correct 29 ms 17408 KB Output is correct
79 Correct 440 ms 61292 KB Output is correct
80 Correct 8 ms 12244 KB Output is correct
81 Correct 95 ms 19912 KB Output is correct
82 Correct 351 ms 34160 KB Output is correct
83 Correct 405 ms 32028 KB Output is correct
84 Correct 427 ms 32056 KB Output is correct
85 Correct 419 ms 32208 KB Output is correct
86 Correct 432 ms 33176 KB Output is correct
87 Correct 420 ms 33112 KB Output is correct