oj.uz

Submission #698364

# Submission time Handle Problem Language Result Execution time Memory
698364 2023-02-13T09:39:01 Z _martynas Network (BOI15_net) C++11
100 / 100
 510 ms 70508 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 5 ms 11988 KB Output is correct
2 Correct 6 ms 12060 KB Output is correct
3 Correct 8 ms 11988 KB Output is correct
4 Correct 6 ms 11988 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 11964 KB Output is correct
8 Correct 6 ms 11988 KB Output is correct
9 Correct 7 ms 12092 KB Output is correct
10 Correct 7 ms 11988 KB Output is correct
11 Correct 6 ms 11988 KB Output is correct
12 Correct 9 ms 11988 KB Output is correct
13 Correct 6 ms 11988 KB Output is correct
14 Correct 7 ms 11988 KB Output is correct
15 Correct 6 ms 11988 KB Output is correct
16 Correct 6 ms 11988 KB Output is correct
17 Correct 6 ms 12040 KB Output is correct
18 Correct 6 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 5 ms 11988 KB Output is correct
2 Correct 6 ms 12060 KB Output is correct
3 Correct 8 ms 11988 KB Output is correct
4 Correct 6 ms 11988 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 11964 KB Output is correct
8 Correct 6 ms 11988 KB Output is correct
9 Correct 7 ms 12092 KB Output is correct
10 Correct 7 ms 11988 KB Output is correct
11 Correct 6 ms 11988 KB Output is correct
12 Correct 9 ms 11988 KB Output is correct
13 Correct 6 ms 11988 KB Output is correct
14 Correct 7 ms 11988 KB Output is correct
15 Correct 6 ms 11988 KB Output is correct
16 Correct 6 ms 11988 KB Output is correct
17 Correct 6 ms 12040 KB Output is correct
18 Correct 6 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 6 ms 11988 KB Output is correct
22 Correct 8 ms 12244 KB Output is correct
23 Correct 9 ms 12244 KB Output is correct
24 Correct 8 ms 12244 KB Output is correct
25 Correct 7 ms 12116 KB Output is correct
26 Correct 8 ms 12116 KB Output is correct
27 Correct 7 ms 12120 KB Output is correct
28 Correct 7 ms 12116 KB Output is correct
29 Correct 6 ms 12116 KB Output is correct
30 Correct 7 ms 11988 KB Output is correct
31 Correct 7 ms 12116 KB Output is correct
32 Correct 6 ms 12008 KB Output is correct
33 Correct 6 ms 12064 KB Output is correct
34 Correct 6 ms 11988 KB Output is correct
35 Correct 6 ms 11988 KB Output is correct
36 Correct 6 ms 11988 KB Output is correct
37 Correct 7 ms 12116 KB Output is correct
38 Correct 6 ms 12116 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 12116 KB Output is correct
43 Correct 7 ms 12116 KB Output is correct
44 Correct 6 ms 11964 KB Output is correct
45 Correct 8 ms 11988 KB Output is correct
46 Correct 6 ms 12116 KB Output is correct
47 Correct 7 ms 12064 KB Output is correct
48 Correct 7 ms 11988 KB Output is correct
49 Correct 7 ms 12116 KB Output is correct
50 Correct 6 ms 11988 KB Output is correct
51 Correct 6 ms 11988 KB Output is correct
52 Correct 6 ms 11988 KB Output is correct
53 Correct 6 ms 12116 KB Output is correct
54 Correct 6 ms 11988 KB Output is correct
55 Correct 6 ms 11988 KB Output is correct
56 Correct 8 ms 11988 KB Output is correct
57 Correct 6 ms 12116 KB Output is correct
58 Correct 7 ms 12152 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 11988 KB Output is correct
2 Correct 6 ms 12060 KB Output is correct
3 Correct 8 ms 11988 KB Output is correct
4 Correct 6 ms 11988 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 11964 KB Output is correct
8 Correct 6 ms 11988 KB Output is correct
9 Correct 7 ms 12092 KB Output is correct
10 Correct 7 ms 11988 KB Output is correct
11 Correct 6 ms 11988 KB Output is correct
12 Correct 9 ms 11988 KB Output is correct
13 Correct 6 ms 11988 KB Output is correct
14 Correct 7 ms 11988 KB Output is correct
15 Correct 6 ms 11988 KB Output is correct
16 Correct 6 ms 11988 KB Output is correct
17 Correct 6 ms 12040 KB Output is correct
18 Correct 6 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 6 ms 11988 KB Output is correct
22 Correct 8 ms 12244 KB Output is correct
23 Correct 9 ms 12244 KB Output is correct
24 Correct 8 ms 12244 KB Output is correct
25 Correct 7 ms 12116 KB Output is correct
26 Correct 8 ms 12116 KB Output is correct
27 Correct 7 ms 12120 KB Output is correct
28 Correct 7 ms 12116 KB Output is correct
29 Correct 6 ms 12116 KB Output is correct
30 Correct 7 ms 11988 KB Output is correct
31 Correct 7 ms 12116 KB Output is correct
32 Correct 6 ms 12008 KB Output is correct
33 Correct 6 ms 12064 KB Output is correct
34 Correct 6 ms 11988 KB Output is correct
35 Correct 6 ms 11988 KB Output is correct
36 Correct 6 ms 11988 KB Output is correct
37 Correct 7 ms 12116 KB Output is correct
38 Correct 6 ms 12116 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 12116 KB Output is correct
43 Correct 7 ms 12116 KB Output is correct
44 Correct 6 ms 11964 KB Output is correct
45 Correct 8 ms 11988 KB Output is correct
46 Correct 6 ms 12116 KB Output is correct
47 Correct 7 ms 12064 KB Output is correct
48 Correct 7 ms 11988 KB Output is correct
49 Correct 7 ms 12116 KB Output is correct
50 Correct 6 ms 11988 KB Output is correct
51 Correct 6 ms 11988 KB Output is correct
52 Correct 6 ms 11988 KB Output is correct
53 Correct 6 ms 12116 KB Output is correct
54 Correct 6 ms 11988 KB Output is correct
55 Correct 6 ms 11988 KB Output is correct
56 Correct 8 ms 11988 KB Output is correct
57 Correct 6 ms 12116 KB Output is correct
58 Correct 7 ms 12152 KB Output is correct
59 Correct 386 ms 43060 KB Output is correct
60 Correct 390 ms 35352 KB Output is correct
61 Correct 6 ms 11988 KB Output is correct
62 Correct 6 ms 11988 KB Output is correct
63 Correct 387 ms 38032 KB Output is correct
64 Correct 8 ms 12560 KB Output is correct
65 Correct 15 ms 14264 KB Output is correct
66 Correct 148 ms 31780 KB Output is correct
67 Correct 476 ms 50540 KB Output is correct
68 Correct 510 ms 51900 KB Output is correct
69 Correct 20 ms 13724 KB Output is correct
70 Correct 98 ms 29912 KB Output is correct
71 Correct 509 ms 70508 KB Output is correct
72 Correct 384 ms 66664 KB Output is correct
73 Correct 81 ms 18192 KB Output is correct
74 Correct 403 ms 34836 KB Output is correct
75 Correct 31 ms 16636 KB Output is correct
76 Correct 366 ms 54652 KB Output is correct
77 Correct 341 ms 55580 KB Output is correct
78 Correct 28 ms 15820 KB Output is correct
79 Correct 484 ms 47724 KB Output is correct
80 Correct 8 ms 12372 KB Output is correct
81 Correct 104 ms 25720 KB Output is correct
82 Correct 409 ms 53132 KB Output is correct
83 Correct 422 ms 34072 KB Output is correct
84 Correct 402 ms 34184 KB Output is correct
85 Correct 456 ms 33968 KB Output is correct
86 Correct 422 ms 35316 KB Output is correct
87 Correct 442 ms 35476 KB Output is correct