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Submission #997025

# Submission time Handle Problem Language Result Execution time Memory
997025 2024-06-11T15:35:00 Z underwaterkillerwhale Network (BOI15_net) C++17
100 / 100
 317 ms 118856 KB 
#include <bits/stdc++.h>
#define se              second
#define fs              first
#define mp              make_pair
#define pb              push_back
#define ll              long long
#define ii              pair<ll,ll>
#define ld              long double
#define SZ(v)           (int)v.size()
#define ALL(v)          v.begin(), v.end()
#define bit(msk, i)     ((msk >> i) & 1)
#define iter(id, v)     for(auto id : v)
#define rep(i,m,n)      for(int i=(m); i<=(n); i++)
#define reb(i,m,n)      for(int i=(m); i>=(n); i--)

using namespace std;

mt19937_64 rd(chrono :: steady_clock :: now().time_since_epoch().count());
ll Rand(ll l, ll r) { return uniform_int_distribution<ll> (l, r)(rd); }

const int N  = 5e5 + 7;
const int Mod = 998244353;
const int szBL = 916;
const ll INF = 1e18;
const int BASE = 137;

int n;
vector<int> ke[N];

int in[N], out[N];

vector<pair<int,int>> Ans;

vector<int> dfs (int u, int p) {
    if (SZ(ke[u]) == 1) return vector<int> (1, u);
    vector<int> prv;
    iter (&v, ke[u]) {
        if (v == p) continue;
        vector<int> cur = dfs (v, u);
        if (SZ(cur) > SZ(prv)) swap(cur, prv);
        while (SZ(prv) + SZ(cur) > 2 && cur.size()) {
            Ans.push_back(mp(cur.back(), prv.back()));
            cur.pop_back();
            prv.pop_back();
        }
        iter (&id, cur) prv.push_back(id);
    }
    return prv;
}

void solution () {
    cin >> n;
    rep (i, 1, n - 1) {
        int u, v;
        cin >> u >> v;
        ke[u].push_back(v);
        ke[v].push_back(u);
    }
    int root = 1;
    rep (i, 1, n) if (SZ(ke[i]) > 1) root = i;
    vector<int> cur = dfs (root, 0);
    if (SZ(cur) == 1) cur.push_back(root);
    Ans.push_back(mp(cur[0], cur[1]));
    cout << SZ(Ans) <<"\n";
    iter (&id, Ans) cout << id.fs<< " "<<id.se <<"\n";


}
#define file(name) freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout);
int main () {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

//    file ("fbuy");
    int num_Test = 1;
//    cin >> num_Test;
    while (num_Test--)
        solution();
}
/*
7
1 2 4
2 3 12
3 4 2
4 5 48
5 6 2
6 7 123

*/

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 13660 KB Output is correct
2 Correct 2 ms 13660 KB Output is correct
3 Correct 2 ms 13660 KB Output is correct
4 Correct 4 ms 13660 KB Output is correct
5 Correct 2 ms 13660 KB Output is correct
6 Correct 3 ms 13656 KB Output is correct
7 Correct 3 ms 13660 KB Output is correct
8 Correct 2 ms 13880 KB Output is correct
9 Correct 3 ms 13656 KB Output is correct
10 Correct 2 ms 13660 KB Output is correct
11 Correct 2 ms 13888 KB Output is correct
12 Correct 2 ms 13660 KB Output is correct
13 Correct 3 ms 13660 KB Output is correct
14 Correct 3 ms 13660 KB Output is correct
15 Correct 2 ms 13660 KB Output is correct
16 Correct 3 ms 13656 KB Output is correct
17 Correct 4 ms 13660 KB Output is correct
18 Correct 3 ms 13656 KB Output is correct
19 Correct 3 ms 13656 KB Output is correct
20 Correct 3 ms 13656 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 13660 KB Output is correct
2 Correct 2 ms 13660 KB Output is correct
3 Correct 2 ms 13660 KB Output is correct
4 Correct 4 ms 13660 KB Output is correct
5 Correct 2 ms 13660 KB Output is correct
6 Correct 3 ms 13656 KB Output is correct
7 Correct 3 ms 13660 KB Output is correct
8 Correct 2 ms 13880 KB Output is correct
9 Correct 3 ms 13656 KB Output is correct
10 Correct 2 ms 13660 KB Output is correct
11 Correct 2 ms 13888 KB Output is correct
12 Correct 2 ms 13660 KB Output is correct
13 Correct 3 ms 13660 KB Output is correct
14 Correct 3 ms 13660 KB Output is correct
15 Correct 2 ms 13660 KB Output is correct
16 Correct 3 ms 13656 KB Output is correct
17 Correct 4 ms 13660 KB Output is correct
18 Correct 3 ms 13656 KB Output is correct
19 Correct 3 ms 13656 KB Output is correct
20 Correct 3 ms 13656 KB Output is correct
21 Correct 3 ms 13660 KB Output is correct
22 Correct 3 ms 13916 KB Output is correct
23 Correct 3 ms 13912 KB Output is correct
24 Correct 3 ms 13916 KB Output is correct
25 Correct 3 ms 13916 KB Output is correct
26 Correct 2 ms 13916 KB Output is correct
27 Correct 4 ms 13916 KB Output is correct
28 Correct 3 ms 13916 KB Output is correct
29 Correct 3 ms 13916 KB Output is correct
30 Correct 2 ms 13656 KB Output is correct
31 Correct 3 ms 13916 KB Output is correct
32 Correct 2 ms 13660 KB Output is correct
33 Correct 3 ms 13656 KB Output is correct
34 Correct 2 ms 13660 KB Output is correct
35 Correct 2 ms 13660 KB Output is correct
36 Correct 3 ms 13816 KB Output is correct
37 Correct 3 ms 13916 KB Output is correct
38 Correct 3 ms 13888 KB Output is correct
39 Correct 2 ms 13912 KB Output is correct
40 Correct 2 ms 13660 KB Output is correct
41 Correct 2 ms 13660 KB Output is correct
42 Correct 2 ms 13752 KB Output is correct
43 Correct 3 ms 13912 KB Output is correct
44 Correct 2 ms 13660 KB Output is correct
45 Correct 2 ms 13660 KB Output is correct
46 Correct 3 ms 13916 KB Output is correct
47 Correct 3 ms 13660 KB Output is correct
48 Correct 2 ms 13660 KB Output is correct
49 Correct 2 ms 13916 KB Output is correct
50 Correct 2 ms 13656 KB Output is correct
51 Correct 2 ms 13656 KB Output is correct
52 Correct 2 ms 13916 KB Output is correct
53 Correct 2 ms 13916 KB Output is correct
54 Correct 2 ms 13660 KB Output is correct
55 Correct 3 ms 13660 KB Output is correct
56 Correct 2 ms 13660 KB Output is correct
57 Correct 2 ms 13916 KB Output is correct
58 Correct 3 ms 13916 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 13660 KB Output is correct
2 Correct 2 ms 13660 KB Output is correct
3 Correct 2 ms 13660 KB Output is correct
4 Correct 4 ms 13660 KB Output is correct
5 Correct 2 ms 13660 KB Output is correct
6 Correct 3 ms 13656 KB Output is correct
7 Correct 3 ms 13660 KB Output is correct
8 Correct 2 ms 13880 KB Output is correct
9 Correct 3 ms 13656 KB Output is correct
10 Correct 2 ms 13660 KB Output is correct
11 Correct 2 ms 13888 KB Output is correct
12 Correct 2 ms 13660 KB Output is correct
13 Correct 3 ms 13660 KB Output is correct
14 Correct 3 ms 13660 KB Output is correct
15 Correct 2 ms 13660 KB Output is correct
16 Correct 3 ms 13656 KB Output is correct
17 Correct 4 ms 13660 KB Output is correct
18 Correct 3 ms 13656 KB Output is correct
19 Correct 3 ms 13656 KB Output is correct
20 Correct 3 ms 13656 KB Output is correct
21 Correct 3 ms 13660 KB Output is correct
22 Correct 3 ms 13916 KB Output is correct
23 Correct 3 ms 13912 KB Output is correct
24 Correct 3 ms 13916 KB Output is correct
25 Correct 3 ms 13916 KB Output is correct
26 Correct 2 ms 13916 KB Output is correct
27 Correct 4 ms 13916 KB Output is correct
28 Correct 3 ms 13916 KB Output is correct
29 Correct 3 ms 13916 KB Output is correct
30 Correct 2 ms 13656 KB Output is correct
31 Correct 3 ms 13916 KB Output is correct
32 Correct 2 ms 13660 KB Output is correct
33 Correct 3 ms 13656 KB Output is correct
34 Correct 2 ms 13660 KB Output is correct
35 Correct 2 ms 13660 KB Output is correct
36 Correct 3 ms 13816 KB Output is correct
37 Correct 3 ms 13916 KB Output is correct
38 Correct 3 ms 13888 KB Output is correct
39 Correct 2 ms 13912 KB Output is correct
40 Correct 2 ms 13660 KB Output is correct
41 Correct 2 ms 13660 KB Output is correct
42 Correct 2 ms 13752 KB Output is correct
43 Correct 3 ms 13912 KB Output is correct
44 Correct 2 ms 13660 KB Output is correct
45 Correct 2 ms 13660 KB Output is correct
46 Correct 3 ms 13916 KB Output is correct
47 Correct 3 ms 13660 KB Output is correct
48 Correct 2 ms 13660 KB Output is correct
49 Correct 2 ms 13916 KB Output is correct
50 Correct 2 ms 13656 KB Output is correct
51 Correct 2 ms 13656 KB Output is correct
52 Correct 2 ms 13916 KB Output is correct
53 Correct 2 ms 13916 KB Output is correct
54 Correct 2 ms 13660 KB Output is correct
55 Correct 3 ms 13660 KB Output is correct
56 Correct 2 ms 13660 KB Output is correct
57 Correct 2 ms 13916 KB Output is correct
58 Correct 3 ms 13916 KB Output is correct
59 Correct 154 ms 35228 KB Output is correct
60 Correct 162 ms 37316 KB Output is correct
61 Correct 2 ms 13660 KB Output is correct
62 Correct 2 ms 13660 KB Output is correct
63 Correct 130 ms 32920 KB Output is correct
64 Correct 4 ms 14680 KB Output is correct
65 Correct 9 ms 17244 KB Output is correct
66 Correct 58 ms 39700 KB Output is correct
67 Correct 288 ms 118856 KB Output is correct
68 Correct 317 ms 91732 KB Output is correct
69 Correct 6 ms 14728 KB Output is correct
70 Correct 46 ms 22252 KB Output is correct
71 Correct 160 ms 40396 KB Output is correct
72 Correct 148 ms 39488 KB Output is correct
73 Correct 38 ms 20176 KB Output is correct
74 Correct 211 ms 36288 KB Output is correct
75 Correct 16 ms 16860 KB Output is correct
76 Correct 171 ms 40112 KB Output is correct
77 Correct 144 ms 40356 KB Output is correct
78 Correct 19 ms 19264 KB Output is correct
79 Correct 296 ms 72452 KB Output is correct
80 Correct 4 ms 14168 KB Output is correct
81 Correct 49 ms 22192 KB Output is correct
82 Correct 190 ms 38332 KB Output is correct
83 Correct 218 ms 36236 KB Output is correct
84 Correct 195 ms 36292 KB Output is correct
85 Correct 237 ms 36436 KB Output is correct
86 Correct 217 ms 37316 KB Output is correct
87 Correct 233 ms 37316 KB Output is correct