oj.uz

Submission #656126

# Submission time Handle Problem Language Result Execution time Memory
656126 2022-11-06T10:21:28 Z Kahou Network (BOI15_net) C++14
100 / 100
 557 ms 90312 KB 
#include<bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define endl '\n'
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int N = 5e5 + 50;
int n, sub[N], k, par[N], t;
vector<int> adj[N];
vector<int> vc[N];
set<pii> st;
vector<pii> out;

void dfs(int u, int p) {
        par[u] = p;
        for (int v:adj[u]) {
                if (v == p) continue;
                dfs(v, u);
                sub[u] += sub[v];
        }
}

void dfs2(int u, int p) {
        if (adj[u].size() == 1) {
                vc[t].push_back(u);
        }
        for (int v:adj[u]) {
                if (v == p) continue;
                dfs2(v, u);
        }
}

void solve() {
        cin >> n;
        for (int i = 1; i <= n-1; i++) {
                int u, v;
                cin >> u >> v;
                adj[u].push_back(v);
                adj[v].push_back(u);
        }
        for (int u = 1; u <= n; u++) {
                if (adj[u].size() == 1) {
                        k++;
                        sub[u] = 1;
                }
        }
        dfs(1, 0);
        int r = 0;
        for (int u = 1; u <= n; u++) {
                if (adj[u].size() == 1) continue;
                bool flg = 1;
                for (int v:adj[u]) {
                        if (v == par[u]) flg = flg&&(k-sub[u] <= k/2);
                        else flg = flg&&(sub[v] <= k/2);
                }
                if (flg) {
                        r = u;
                        break;
                }
        }
        for (int u:adj[r]) {
                t++;
                dfs2(u, r);
        }
        for (int i = 1; i <= t; i++) {
                st.insert({-vc[i].size(), i});
        }
        while (st.size() >= 2) {
                auto it = st.begin();
                int A = it->S; it++;
                int B = it->S;

                out.push_back({vc[A].back(), vc[B].back()});

                st.erase({-vc[A].size(), A});
                st.erase({-vc[B].size(), B});

                vc[A].pop_back();
                vc[B].pop_back();
                if (!vc[A].empty()) st.insert({-vc[A].size(), A});
                if (!vc[B].empty()) st.insert({-vc[B].size(), B});
        }
        if (st.size()) {
                int A = st.begin()->S;
                int u = vc[A].back();
                out.push_back({u, r});
        }

        cout << out.size() << endl;
        for (pii x:out) {
                cout << x.F << ' ' << x.S << endl;
        }
}

int main() {
        ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
        solve();
        return 0;
}

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23792 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 13 ms 23764 KB Output is correct
4 Correct 12 ms 23764 KB Output is correct
5 Correct 12 ms 23776 KB Output is correct
6 Correct 13 ms 23764 KB Output is correct
7 Correct 13 ms 23740 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 13 ms 23796 KB Output is correct
10 Correct 12 ms 23764 KB Output is correct
11 Correct 15 ms 23844 KB Output is correct
12 Correct 13 ms 23764 KB Output is correct
13 Correct 15 ms 23816 KB Output is correct
14 Correct 13 ms 23780 KB Output is correct
15 Correct 13 ms 23824 KB Output is correct
16 Correct 12 ms 23764 KB Output is correct
17 Correct 13 ms 23764 KB Output is correct
18 Correct 13 ms 23764 KB Output is correct
19 Correct 12 ms 23764 KB Output is correct
20 Correct 13 ms 23704 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23792 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 13 ms 23764 KB Output is correct
4 Correct 12 ms 23764 KB Output is correct
5 Correct 12 ms 23776 KB Output is correct
6 Correct 13 ms 23764 KB Output is correct
7 Correct 13 ms 23740 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 13 ms 23796 KB Output is correct
10 Correct 12 ms 23764 KB Output is correct
11 Correct 15 ms 23844 KB Output is correct
12 Correct 13 ms 23764 KB Output is correct
13 Correct 15 ms 23816 KB Output is correct
14 Correct 13 ms 23780 KB Output is correct
15 Correct 13 ms 23824 KB Output is correct
16 Correct 12 ms 23764 KB Output is correct
17 Correct 13 ms 23764 KB Output is correct
18 Correct 13 ms 23764 KB Output is correct
19 Correct 12 ms 23764 KB Output is correct
20 Correct 13 ms 23704 KB Output is correct
21 Correct 14 ms 23764 KB Output is correct
22 Correct 13 ms 23892 KB Output is correct
23 Correct 13 ms 23876 KB Output is correct
24 Correct 13 ms 24020 KB Output is correct
25 Correct 13 ms 23892 KB Output is correct
26 Correct 13 ms 23892 KB Output is correct
27 Correct 14 ms 23892 KB Output is correct
28 Correct 13 ms 23892 KB Output is correct
29 Correct 13 ms 23800 KB Output is correct
30 Correct 14 ms 23764 KB Output is correct
31 Correct 13 ms 23892 KB Output is correct
32 Correct 16 ms 23764 KB Output is correct
33 Correct 13 ms 23764 KB Output is correct
34 Correct 14 ms 23764 KB Output is correct
35 Correct 15 ms 23736 KB Output is correct
36 Correct 13 ms 23764 KB Output is correct
37 Correct 13 ms 23764 KB Output is correct
38 Correct 13 ms 23820 KB Output is correct
39 Correct 12 ms 23764 KB Output is correct
40 Correct 12 ms 23720 KB Output is correct
41 Correct 13 ms 23732 KB Output is correct
42 Correct 13 ms 23764 KB Output is correct
43 Correct 13 ms 23892 KB Output is correct
44 Correct 12 ms 23764 KB Output is correct
45 Correct 13 ms 23756 KB Output is correct
46 Correct 13 ms 23784 KB Output is correct
47 Correct 14 ms 23764 KB Output is correct
48 Correct 12 ms 23764 KB Output is correct
49 Correct 13 ms 23892 KB Output is correct
50 Correct 13 ms 23820 KB Output is correct
51 Correct 12 ms 23764 KB Output is correct
52 Correct 14 ms 23812 KB Output is correct
53 Correct 13 ms 23764 KB Output is correct
54 Correct 12 ms 23764 KB Output is correct
55 Correct 15 ms 23760 KB Output is correct
56 Correct 13 ms 23724 KB Output is correct
57 Correct 13 ms 23796 KB Output is correct
58 Correct 14 ms 23900 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23792 KB Output is correct
2 Correct 12 ms 23764 KB Output is correct
3 Correct 13 ms 23764 KB Output is correct
4 Correct 12 ms 23764 KB Output is correct
5 Correct 12 ms 23776 KB Output is correct
6 Correct 13 ms 23764 KB Output is correct
7 Correct 13 ms 23740 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 13 ms 23796 KB Output is correct
10 Correct 12 ms 23764 KB Output is correct
11 Correct 15 ms 23844 KB Output is correct
12 Correct 13 ms 23764 KB Output is correct
13 Correct 15 ms 23816 KB Output is correct
14 Correct 13 ms 23780 KB Output is correct
15 Correct 13 ms 23824 KB Output is correct
16 Correct 12 ms 23764 KB Output is correct
17 Correct 13 ms 23764 KB Output is correct
18 Correct 13 ms 23764 KB Output is correct
19 Correct 12 ms 23764 KB Output is correct
20 Correct 13 ms 23704 KB Output is correct
21 Correct 14 ms 23764 KB Output is correct
22 Correct 13 ms 23892 KB Output is correct
23 Correct 13 ms 23876 KB Output is correct
24 Correct 13 ms 24020 KB Output is correct
25 Correct 13 ms 23892 KB Output is correct
26 Correct 13 ms 23892 KB Output is correct
27 Correct 14 ms 23892 KB Output is correct
28 Correct 13 ms 23892 KB Output is correct
29 Correct 13 ms 23800 KB Output is correct
30 Correct 14 ms 23764 KB Output is correct
31 Correct 13 ms 23892 KB Output is correct
32 Correct 16 ms 23764 KB Output is correct
33 Correct 13 ms 23764 KB Output is correct
34 Correct 14 ms 23764 KB Output is correct
35 Correct 15 ms 23736 KB Output is correct
36 Correct 13 ms 23764 KB Output is correct
37 Correct 13 ms 23764 KB Output is correct
38 Correct 13 ms 23820 KB Output is correct
39 Correct 12 ms 23764 KB Output is correct
40 Correct 12 ms 23720 KB Output is correct
41 Correct 13 ms 23732 KB Output is correct
42 Correct 13 ms 23764 KB Output is correct
43 Correct 13 ms 23892 KB Output is correct
44 Correct 12 ms 23764 KB Output is correct
45 Correct 13 ms 23756 KB Output is correct
46 Correct 13 ms 23784 KB Output is correct
47 Correct 14 ms 23764 KB Output is correct
48 Correct 12 ms 23764 KB Output is correct
49 Correct 13 ms 23892 KB Output is correct
50 Correct 13 ms 23820 KB Output is correct
51 Correct 12 ms 23764 KB Output is correct
52 Correct 14 ms 23812 KB Output is correct
53 Correct 13 ms 23764 KB Output is correct
54 Correct 12 ms 23764 KB Output is correct
55 Correct 15 ms 23760 KB Output is correct
56 Correct 13 ms 23724 KB Output is correct
57 Correct 13 ms 23796 KB Output is correct
58 Correct 14 ms 23900 KB Output is correct
59 Correct 457 ms 58276 KB Output is correct
60 Correct 456 ms 52080 KB Output is correct
61 Correct 13 ms 23764 KB Output is correct
62 Correct 13 ms 23764 KB Output is correct
63 Correct 394 ms 52300 KB Output is correct
64 Correct 15 ms 24348 KB Output is correct
65 Correct 24 ms 26360 KB Output is correct
66 Correct 165 ms 45532 KB Output is correct
67 Correct 534 ms 66768 KB Output is correct
68 Correct 531 ms 67896 KB Output is correct
69 Correct 22 ms 25756 KB Output is correct
70 Correct 125 ms 44064 KB Output is correct
71 Correct 472 ms 90312 KB Output is correct
72 Correct 468 ms 85668 KB Output is correct
73 Correct 99 ms 32088 KB Output is correct
74 Correct 483 ms 50160 KB Output is correct
75 Correct 41 ms 29260 KB Output is correct
76 Correct 388 ms 70688 KB Output is correct
77 Correct 421 ms 71712 KB Output is correct
78 Correct 35 ms 28108 KB Output is correct
79 Correct 557 ms 63848 KB Output is correct
80 Correct 15 ms 24148 KB Output is correct
81 Correct 130 ms 40040 KB Output is correct
82 Correct 492 ms 69748 KB Output is correct
83 Correct 456 ms 50148 KB Output is correct
84 Correct 515 ms 50780 KB Output is correct
85 Correct 451 ms 50680 KB Output is correct
86 Correct 444 ms 52448 KB Output is correct
87 Correct 463 ms 52544 KB Output is correct