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Submission #122204

# Submission time Handle Problem Language Result Execution time Memory
122204 2019-06-27T20:23:51 Z Gustav Network (BOI15_net) C++14
100 / 100
 605 ms 45340 KB 
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pi;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<pi> vpi;
typedef vector<vi> vvi;
const int inf = 0x3f3f3f3f;
const ll linf = 123456789012345678;
const ll mod = 998244353;
#pragma GCC optimize("Ofast")
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " = " << x << endl

int n;
vvi conn;
vpi ans;

pi dfs(int node, int par){
    if(conn[node].size() == 1) return {node, -1};
    pi m = {-1, -1};
    for(auto x : conn[node]){
        if(x == par) continue;
        pi r = dfs(x, node);
        if(m.first == -1) m = r;
        else{
            if(m.second != -1 || r.second != -1){
                ans.push_back({m.first, r.first});
                if(m.second == -1) m = {r.second, m.second};
                else m = {m.second, r.second};
            }
            else{
                m.second = r.first;
            }
        }
    }
    return m;
}

int main(){
    cin.sync_with_stdio(false);
    cin.tie(0);
    
    cin >> n;
    conn = vvi(n);
    for(int i = 0; i < n-1; i++){
        int u, v;
        cin >> u >> v;
        u--, v--;
        conn[u].push_back(v);
        conn[v].push_back(u);
    }

    int root = 0;
    while(conn[root].size() == 1) root++;

    pi r = dfs(root, -1);
    if(r.second != -1){
        ans.push_back({r.first, r.second});
    }
    else{
        ans.push_back({root, r.first});
    }

    cout << ans.size() << "\n";
    for(int i = 0; i < ans.size(); i++) cout << ans[i].first+1 << " " << ans[i].second+1 << "\n";
}

Compilation message

net.cpp: In function 'int main()':
net.cpp:68:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 0; i < ans.size(); i++) cout << ans[i].first+1 << " " << ans[i].second+1 << "\n";
                    ~~^~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 384 KB Output is correct
2 Correct 2 ms 256 KB Output is correct
3 Correct 2 ms 384 KB Output is correct
4 Correct 2 ms 384 KB Output is correct
5 Correct 2 ms 384 KB Output is correct
6 Correct 2 ms 384 KB Output is correct
7 Correct 2 ms 384 KB Output is correct
8 Correct 2 ms 384 KB Output is correct
9 Correct 2 ms 384 KB Output is correct
10 Correct 2 ms 384 KB Output is correct
11 Correct 2 ms 384 KB Output is correct
12 Correct 2 ms 384 KB Output is correct
13 Correct 2 ms 384 KB Output is correct
14 Correct 2 ms 384 KB Output is correct
15 Correct 2 ms 384 KB Output is correct
16 Correct 2 ms 384 KB Output is correct
17 Correct 2 ms 384 KB Output is correct
18 Correct 2 ms 384 KB Output is correct
19 Correct 2 ms 384 KB Output is correct
20 Correct 2 ms 384 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 384 KB Output is correct
2 Correct 2 ms 256 KB Output is correct
3 Correct 2 ms 384 KB Output is correct
4 Correct 2 ms 384 KB Output is correct
5 Correct 2 ms 384 KB Output is correct
6 Correct 2 ms 384 KB Output is correct
7 Correct 2 ms 384 KB Output is correct
8 Correct 2 ms 384 KB Output is correct
9 Correct 2 ms 384 KB Output is correct
10 Correct 2 ms 384 KB Output is correct
11 Correct 2 ms 384 KB Output is correct
12 Correct 2 ms 384 KB Output is correct
13 Correct 2 ms 384 KB Output is correct
14 Correct 2 ms 384 KB Output is correct
15 Correct 2 ms 384 KB Output is correct
16 Correct 2 ms 384 KB Output is correct
17 Correct 2 ms 384 KB Output is correct
18 Correct 2 ms 384 KB Output is correct
19 Correct 2 ms 384 KB Output is correct
20 Correct 2 ms 384 KB Output is correct
21 Correct 2 ms 384 KB Output is correct
22 Correct 3 ms 512 KB Output is correct
23 Correct 3 ms 512 KB Output is correct
24 Correct 3 ms 512 KB Output is correct
25 Correct 3 ms 512 KB Output is correct
26 Correct 2 ms 512 KB Output is correct
27 Correct 3 ms 640 KB Output is correct
28 Correct 3 ms 512 KB Output is correct
29 Correct 2 ms 432 KB Output is correct
30 Correct 2 ms 384 KB Output is correct
31 Correct 3 ms 512 KB Output is correct
32 Correct 2 ms 384 KB Output is correct
33 Correct 2 ms 384 KB Output is correct
34 Correct 2 ms 384 KB Output is correct
35 Correct 2 ms 384 KB Output is correct
36 Correct 2 ms 384 KB Output is correct
37 Correct 3 ms 384 KB Output is correct
38 Correct 2 ms 512 KB Output is correct
39 Correct 2 ms 384 KB Output is correct
40 Correct 2 ms 384 KB Output is correct
41 Correct 2 ms 384 KB Output is correct
42 Correct 2 ms 512 KB Output is correct
43 Correct 2 ms 384 KB Output is correct
44 Correct 2 ms 384 KB Output is correct
45 Correct 2 ms 384 KB Output is correct
46 Correct 2 ms 384 KB Output is correct
47 Correct 2 ms 380 KB Output is correct
48 Correct 2 ms 384 KB Output is correct
49 Correct 3 ms 384 KB Output is correct
50 Correct 2 ms 384 KB Output is correct
51 Correct 2 ms 384 KB Output is correct
52 Correct 2 ms 384 KB Output is correct
53 Correct 3 ms 384 KB Output is correct
54 Correct 2 ms 384 KB Output is correct
55 Correct 2 ms 384 KB Output is correct
56 Correct 2 ms 384 KB Output is correct
57 Correct 2 ms 384 KB Output is correct
58 Correct 3 ms 512 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 384 KB Output is correct
2 Correct 2 ms 256 KB Output is correct
3 Correct 2 ms 384 KB Output is correct
4 Correct 2 ms 384 KB Output is correct
5 Correct 2 ms 384 KB Output is correct
6 Correct 2 ms 384 KB Output is correct
7 Correct 2 ms 384 KB Output is correct
8 Correct 2 ms 384 KB Output is correct
9 Correct 2 ms 384 KB Output is correct
10 Correct 2 ms 384 KB Output is correct
11 Correct 2 ms 384 KB Output is correct
12 Correct 2 ms 384 KB Output is correct
13 Correct 2 ms 384 KB Output is correct
14 Correct 2 ms 384 KB Output is correct
15 Correct 2 ms 384 KB Output is correct
16 Correct 2 ms 384 KB Output is correct
17 Correct 2 ms 384 KB Output is correct
18 Correct 2 ms 384 KB Output is correct
19 Correct 2 ms 384 KB Output is correct
20 Correct 2 ms 384 KB Output is correct
21 Correct 2 ms 384 KB Output is correct
22 Correct 3 ms 512 KB Output is correct
23 Correct 3 ms 512 KB Output is correct
24 Correct 3 ms 512 KB Output is correct
25 Correct 3 ms 512 KB Output is correct
26 Correct 2 ms 512 KB Output is correct
27 Correct 3 ms 640 KB Output is correct
28 Correct 3 ms 512 KB Output is correct
29 Correct 2 ms 432 KB Output is correct
30 Correct 2 ms 384 KB Output is correct
31 Correct 3 ms 512 KB Output is correct
32 Correct 2 ms 384 KB Output is correct
33 Correct 2 ms 384 KB Output is correct
34 Correct 2 ms 384 KB Output is correct
35 Correct 2 ms 384 KB Output is correct
36 Correct 2 ms 384 KB Output is correct
37 Correct 3 ms 384 KB Output is correct
38 Correct 2 ms 512 KB Output is correct
39 Correct 2 ms 384 KB Output is correct
40 Correct 2 ms 384 KB Output is correct
41 Correct 2 ms 384 KB Output is correct
42 Correct 2 ms 512 KB Output is correct
43 Correct 2 ms 384 KB Output is correct
44 Correct 2 ms 384 KB Output is correct
45 Correct 2 ms 384 KB Output is correct
46 Correct 2 ms 384 KB Output is correct
47 Correct 2 ms 380 KB Output is correct
48 Correct 2 ms 384 KB Output is correct
49 Correct 3 ms 384 KB Output is correct
50 Correct 2 ms 384 KB Output is correct
51 Correct 2 ms 384 KB Output is correct
52 Correct 2 ms 384 KB Output is correct
53 Correct 3 ms 384 KB Output is correct
54 Correct 2 ms 384 KB Output is correct
55 Correct 2 ms 384 KB Output is correct
56 Correct 2 ms 384 KB Output is correct
57 Correct 2 ms 384 KB Output is correct
58 Correct 3 ms 512 KB Output is correct
59 Correct 439 ms 34912 KB Output is correct
60 Correct 510 ms 38744 KB Output is correct
61 Correct 2 ms 384 KB Output is correct
62 Correct 2 ms 384 KB Output is correct
63 Correct 335 ms 31336 KB Output is correct
64 Correct 4 ms 896 KB Output is correct
65 Correct 12 ms 2688 KB Output is correct
66 Correct 190 ms 19032 KB Output is correct
67 Correct 605 ms 44664 KB Output is correct
68 Correct 569 ms 45340 KB Output is correct
69 Correct 9 ms 1536 KB Output is correct
70 Correct 100 ms 13264 KB Output is correct
71 Correct 324 ms 41828 KB Output is correct
72 Correct 360 ms 40712 KB Output is correct
73 Correct 93 ms 10612 KB Output is correct
74 Correct 498 ms 37744 KB Output is correct
75 Correct 24 ms 4836 KB Output is correct
76 Correct 338 ms 41564 KB Output is correct
77 Correct 348 ms 41692 KB Output is correct
78 Correct 29 ms 4984 KB Output is correct
79 Correct 581 ms 43400 KB Output is correct
80 Correct 4 ms 640 KB Output is correct
81 Correct 109 ms 13552 KB Output is correct
82 Correct 431 ms 39788 KB Output is correct
83 Correct 513 ms 37804 KB Output is correct
84 Correct 514 ms 37740 KB Output is correct
85 Correct 525 ms 37840 KB Output is correct
86 Correct 501 ms 38844 KB Output is correct
87 Correct 507 ms 38848 KB Output is correct