oj.uz

Submission #698363

# Submission time Handle Problem Language Result Execution time Memory
698363 2023-02-13T09:38:18 Z _martynas Network (BOI15_net) C++11
100 / 100
 728 ms 77096 KB 
#include <bits/stdc++.h>

using namespace std;

#define F first
#define S second
#define PB push_back

using pii = pair<int, int>;
using vi = vector<int>;

const int MXN = 5e5+5;

int n;
vi adj[MXN];
int leaf_cnt[MXN];
int root;
vector<vi> leaves;

void dfs1(int u, int p) {
    leaf_cnt[u] = adj[u].size() == 1;
    for(int v : adj[u]) {
        if(v == p) continue;
        dfs1(v, u);
        leaf_cnt[u] += leaf_cnt[v];
    }
}

int dfs2(int u, int p) {
    for(int v : adj[u]) {
        if(v == p) continue;
        if(leaf_cnt[v] > (leaf_cnt[root]+1)/2) {
            return dfs2(v, u);
        }
    }
    return u;
}

void dfs3(int u, int p, vi &l) {
    if(adj[u].size() == 1) l.PB(u);
    for(int v : adj[u]) {
        if(v == p) continue;
        dfs3(v, u, l);
    }
}

int main() {
//    ios::sync_with_stdio(0);
//    cin.tie(0);

    cin >> n;
    for(int i = 0; i < n-1; i++) {
        int a, b; cin >> a >> b;
        adj[a].PB(b);
        adj[b].PB(a);
    }

    for(int i = 1; i <= n; i++) {
        if(adj[i].size() > 1) {
            root = i;
            dfs1(i, -1);
            break;
        }
    }
    root = dfs2(root, -1);
    for(int u : adj[root]) {
        vi l;
        dfs3(u, root, l);
        leaves.PB(l);
    }

    priority_queue<pii> PQ;
    for(int i = 0; i < leaves.size(); i++) {
        PQ.push({leaves[i].size(), i});
    }
    vector<pii> ans;
    while(!PQ.empty()) {
        if(PQ.size() == 1) {
            auto p = PQ.top();
            PQ.pop();
            ans.PB({leaves[p.S].back(), root});
        }
        else {
            auto p_a = PQ.top(); PQ.pop();
            auto p_b = PQ.top(); PQ.pop();
            ans.PB({leaves[p_a.S].back(), leaves[p_b.S].back()});
            leaves[p_a.S].pop_back(), leaves[p_b.S].pop_back();
            p_a.F--, p_b.F--;
            if(p_a.F) PQ.push(p_a);
            if(p_b.F) PQ.push(p_b);
        }
    }
    cout << ans.size() << "\n";
    for(auto p : ans) cout << p.F << " " << p.S << "\n";
    return 0;
}
/*
6
1 2
2 3
2 4
5 4
6 4

8
1 2
2 3
3 4
4 5
3 6
3 7
3 8



*/

Compilation message

net.cpp: In function 'int main()':
net.cpp:73:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   73 |     for(int i = 0; i < leaves.size(); i++) {
      |                    ~~^~~~~~~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 11988 KB Output is correct
2 Correct 7 ms 11988 KB Output is correct
3 Correct 6 ms 11988 KB Output is correct
4 Correct 6 ms 12056 KB Output is correct
5 Correct 7 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 12048 KB Output is correct
9 Correct 6 ms 12056 KB Output is correct
10 Correct 8 ms 11988 KB Output is correct
11 Correct 6 ms 12056 KB Output is correct
12 Correct 8 ms 12056 KB Output is correct
13 Correct 7 ms 11988 KB Output is correct
14 Correct 6 ms 11988 KB Output is correct
15 Correct 6 ms 11988 KB Output is correct
16 Correct 7 ms 11988 KB Output is correct
17 Correct 7 ms 12064 KB Output is correct
18 Correct 7 ms 11988 KB Output is correct
19 Correct 6 ms 12052 KB Output is correct
20 Correct 6 ms 12012 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 11988 KB Output is correct
2 Correct 7 ms 11988 KB Output is correct
3 Correct 6 ms 11988 KB Output is correct
4 Correct 6 ms 12056 KB Output is correct
5 Correct 7 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 12048 KB Output is correct
9 Correct 6 ms 12056 KB Output is correct
10 Correct 8 ms 11988 KB Output is correct
11 Correct 6 ms 12056 KB Output is correct
12 Correct 8 ms 12056 KB Output is correct
13 Correct 7 ms 11988 KB Output is correct
14 Correct 6 ms 11988 KB Output is correct
15 Correct 6 ms 11988 KB Output is correct
16 Correct 7 ms 11988 KB Output is correct
17 Correct 7 ms 12064 KB Output is correct
18 Correct 7 ms 11988 KB Output is correct
19 Correct 6 ms 12052 KB Output is correct
20 Correct 6 ms 12012 KB Output is correct
21 Correct 6 ms 12056 KB Output is correct
22 Correct 9 ms 12124 KB Output is correct
23 Correct 9 ms 12280 KB Output is correct
24 Correct 7 ms 12204 KB Output is correct
25 Correct 8 ms 12208 KB Output is correct
26 Correct 7 ms 12116 KB Output is correct
27 Correct 8 ms 12128 KB Output is correct
28 Correct 7 ms 12124 KB Output is correct
29 Correct 7 ms 12116 KB Output is correct
30 Correct 6 ms 11988 KB Output is correct
31 Correct 9 ms 12116 KB Output is correct
32 Correct 7 ms 12056 KB Output is correct
33 Correct 7 ms 11988 KB Output is correct
34 Correct 8 ms 11968 KB Output is correct
35 Correct 6 ms 12052 KB Output is correct
36 Correct 7 ms 12016 KB Output is correct
37 Correct 7 ms 11988 KB Output is correct
38 Correct 7 ms 12244 KB Output is correct
39 Correct 6 ms 11988 KB Output is correct
40 Correct 6 ms 11988 KB Output is correct
41 Correct 6 ms 11988 KB Output is correct
42 Correct 7 ms 11988 KB Output is correct
43 Correct 8 ms 12116 KB Output is correct
44 Correct 7 ms 12056 KB Output is correct
45 Correct 7 ms 12012 KB Output is correct
46 Correct 7 ms 12052 KB Output is correct
47 Correct 7 ms 12060 KB Output is correct
48 Correct 6 ms 12072 KB Output is correct
49 Correct 7 ms 12136 KB Output is correct
50 Correct 6 ms 11988 KB Output is correct
51 Correct 6 ms 11988 KB Output is correct
52 Correct 7 ms 11992 KB Output is correct
53 Correct 7 ms 12116 KB Output is correct
54 Correct 7 ms 11988 KB Output is correct
55 Correct 7 ms 12056 KB Output is correct
56 Correct 7 ms 11988 KB Output is correct
57 Correct 7 ms 11988 KB Output is correct
58 Correct 10 ms 12116 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 11988 KB Output is correct
2 Correct 7 ms 11988 KB Output is correct
3 Correct 6 ms 11988 KB Output is correct
4 Correct 6 ms 12056 KB Output is correct
5 Correct 7 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 12048 KB Output is correct
9 Correct 6 ms 12056 KB Output is correct
10 Correct 8 ms 11988 KB Output is correct
11 Correct 6 ms 12056 KB Output is correct
12 Correct 8 ms 12056 KB Output is correct
13 Correct 7 ms 11988 KB Output is correct
14 Correct 6 ms 11988 KB Output is correct
15 Correct 6 ms 11988 KB Output is correct
16 Correct 7 ms 11988 KB Output is correct
17 Correct 7 ms 12064 KB Output is correct
18 Correct 7 ms 11988 KB Output is correct
19 Correct 6 ms 12052 KB Output is correct
20 Correct 6 ms 12012 KB Output is correct
21 Correct 6 ms 12056 KB Output is correct
22 Correct 9 ms 12124 KB Output is correct
23 Correct 9 ms 12280 KB Output is correct
24 Correct 7 ms 12204 KB Output is correct
25 Correct 8 ms 12208 KB Output is correct
26 Correct 7 ms 12116 KB Output is correct
27 Correct 8 ms 12128 KB Output is correct
28 Correct 7 ms 12124 KB Output is correct
29 Correct 7 ms 12116 KB Output is correct
30 Correct 6 ms 11988 KB Output is correct
31 Correct 9 ms 12116 KB Output is correct
32 Correct 7 ms 12056 KB Output is correct
33 Correct 7 ms 11988 KB Output is correct
34 Correct 8 ms 11968 KB Output is correct
35 Correct 6 ms 12052 KB Output is correct
36 Correct 7 ms 12016 KB Output is correct
37 Correct 7 ms 11988 KB Output is correct
38 Correct 7 ms 12244 KB Output is correct
39 Correct 6 ms 11988 KB Output is correct
40 Correct 6 ms 11988 KB Output is correct
41 Correct 6 ms 11988 KB Output is correct
42 Correct 7 ms 11988 KB Output is correct
43 Correct 8 ms 12116 KB Output is correct
44 Correct 7 ms 12056 KB Output is correct
45 Correct 7 ms 12012 KB Output is correct
46 Correct 7 ms 12052 KB Output is correct
47 Correct 7 ms 12060 KB Output is correct
48 Correct 6 ms 12072 KB Output is correct
49 Correct 7 ms 12136 KB Output is correct
50 Correct 6 ms 11988 KB Output is correct
51 Correct 6 ms 11988 KB Output is correct
52 Correct 7 ms 11992 KB Output is correct
53 Correct 7 ms 12116 KB Output is correct
54 Correct 7 ms 11988 KB Output is correct
55 Correct 7 ms 12056 KB Output is correct
56 Correct 7 ms 11988 KB Output is correct
57 Correct 7 ms 11988 KB Output is correct
58 Correct 10 ms 12116 KB Output is correct
59 Correct 560 ms 49064 KB Output is correct
60 Correct 642 ms 42244 KB Output is correct
61 Correct 6 ms 11988 KB Output is correct
62 Correct 6 ms 11988 KB Output is correct
63 Correct 564 ms 43328 KB Output is correct
64 Correct 11 ms 12628 KB Output is correct
65 Correct 30 ms 14520 KB Output is correct
66 Correct 208 ms 33828 KB Output is correct
67 Correct 702 ms 57164 KB Output is correct
68 Correct 728 ms 58288 KB Output is correct
69 Correct 19 ms 13804 KB Output is correct
70 Correct 171 ms 32092 KB Output is correct
71 Correct 576 ms 77096 KB Output is correct
72 Correct 565 ms 72956 KB Output is correct
73 Correct 136 ms 19884 KB Output is correct
74 Correct 634 ms 41516 KB Output is correct
75 Correct 67 ms 17224 KB Output is correct
76 Correct 600 ms 61424 KB Output is correct
77 Correct 560 ms 62128 KB Output is correct
78 Correct 51 ms 16368 KB Output is correct
79 Correct 697 ms 54424 KB Output is correct
80 Correct 9 ms 12328 KB Output is correct
81 Correct 187 ms 27760 KB Output is correct
82 Correct 618 ms 59528 KB Output is correct
83 Correct 603 ms 40504 KB Output is correct
84 Correct 613 ms 40668 KB Output is correct
85 Correct 593 ms 40516 KB Output is correct
86 Correct 620 ms 41956 KB Output is correct
87 Correct 624 ms 42148 KB Output is correct