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Submission #729500

# Submission time Handle Problem Language Result Execution time Memory
729500 2023-04-24T08:24:05 Z Tigerpants Network (BOI15_net) C++17
100 / 100
 521 ms 70252 KB 
#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <functional>
#include <set>
#include <map>

using namespace std;

typedef long long int ll;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef pair<ll, ll> pll;
typedef vector<pll> vpll;

#define rep(i, a, b) for (ll i = a; i < b; i++)
#define mp(a, b) make_pair(a, b)
#define sz(a) a.size()
#define pb(a) push_back(a)

ll N;

vvll g;

ll root;

vpll edges;

vll dp_dfs(ll cur, ll par) {
    vll res;
    bool is_leaf = true;
    for (vll::iterator itr = g[cur].begin(); itr != g[cur].end(); itr++) {
        if (*itr == par) continue;
        is_leaf = false;
        vll child = dp_dfs(*itr, cur);
        for (vll::iterator t = child.begin(); t != child.end(); t++) res.pb(*t);
        if (sz(res) >= 3) {
            ll a = res.back(); res.pop_back();
            ll b = res.front(); res.erase(res.begin());
            edges.pb(mp(a, b));
        }
    }
    if (is_leaf) {
        res.pb(cur);
    }
    return res;
} 

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> N;
    g.resize(N);
    rep(i, 0, N - 1) {
        ll tmpa, tmpb;
        cin >> tmpa >> tmpb;
        tmpa--; tmpb--;
        g[tmpa].pb(tmpb);
        g[tmpb].pb(tmpa);
    }

    root = 0;
    while (sz(g[root]) == 1) root++;

    vll res = dp_dfs(root, -1);
    if (sz(res) == 1) {
        edges.pb(mp(res[0], root));
    } else {
        edges.pb(mp(res[0], res[1]));
    }

    cout << sz(edges) << "\n";
    for (vpll::iterator itr = edges.begin(); itr != edges.end(); itr++) {
        cout << itr->first + 1 << " " << itr->second + 1 << "\n";
    }
    cout << flush;

    return 0;
}

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 1 ms 212 KB Output is correct
10 Correct 1 ms 316 KB Output is correct
11 Correct 1 ms 212 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 1 ms 212 KB Output is correct
14 Correct 1 ms 212 KB Output is correct
15 Correct 1 ms 212 KB Output is correct
16 Correct 1 ms 316 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 1 ms 324 KB Output is correct
19 Correct 0 ms 212 KB Output is correct
20 Correct 1 ms 212 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 1 ms 212 KB Output is correct
10 Correct 1 ms 316 KB Output is correct
11 Correct 1 ms 212 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 1 ms 212 KB Output is correct
14 Correct 1 ms 212 KB Output is correct
15 Correct 1 ms 212 KB Output is correct
16 Correct 1 ms 316 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 1 ms 324 KB Output is correct
19 Correct 0 ms 212 KB Output is correct
20 Correct 1 ms 212 KB Output is correct
21 Correct 1 ms 212 KB Output is correct
22 Correct 1 ms 468 KB Output is correct
23 Correct 1 ms 468 KB Output is correct
24 Correct 2 ms 468 KB Output is correct
25 Correct 1 ms 468 KB Output is correct
26 Correct 1 ms 340 KB Output is correct
27 Correct 1 ms 460 KB Output is correct
28 Correct 2 ms 468 KB Output is correct
29 Correct 1 ms 340 KB Output is correct
30 Correct 1 ms 320 KB Output is correct
31 Correct 2 ms 464 KB Output is correct
32 Correct 1 ms 212 KB Output is correct
33 Correct 1 ms 320 KB Output is correct
34 Correct 1 ms 212 KB Output is correct
35 Correct 1 ms 316 KB Output is correct
36 Correct 1 ms 212 KB Output is correct
37 Correct 1 ms 340 KB Output is correct
38 Correct 1 ms 468 KB Output is correct
39 Correct 1 ms 212 KB Output is correct
40 Correct 0 ms 320 KB Output is correct
41 Correct 1 ms 212 KB Output is correct
42 Correct 1 ms 340 KB Output is correct
43 Correct 1 ms 320 KB Output is correct
44 Correct 1 ms 212 KB Output is correct
45 Correct 1 ms 340 KB Output is correct
46 Correct 1 ms 340 KB Output is correct
47 Correct 1 ms 212 KB Output is correct
48 Correct 1 ms 340 KB Output is correct
49 Correct 1 ms 340 KB Output is correct
50 Correct 1 ms 212 KB Output is correct
51 Correct 1 ms 212 KB Output is correct
52 Correct 1 ms 340 KB Output is correct
53 Correct 1 ms 340 KB Output is correct
54 Correct 1 ms 212 KB Output is correct
55 Correct 1 ms 340 KB Output is correct
56 Correct 1 ms 316 KB Output is correct
57 Correct 1 ms 340 KB Output is correct
58 Correct 1 ms 460 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 1 ms 212 KB Output is correct
10 Correct 1 ms 316 KB Output is correct
11 Correct 1 ms 212 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 1 ms 212 KB Output is correct
14 Correct 1 ms 212 KB Output is correct
15 Correct 1 ms 212 KB Output is correct
16 Correct 1 ms 316 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 1 ms 324 KB Output is correct
19 Correct 0 ms 212 KB Output is correct
20 Correct 1 ms 212 KB Output is correct
21 Correct 1 ms 212 KB Output is correct
22 Correct 1 ms 468 KB Output is correct
23 Correct 1 ms 468 KB Output is correct
24 Correct 2 ms 468 KB Output is correct
25 Correct 1 ms 468 KB Output is correct
26 Correct 1 ms 340 KB Output is correct
27 Correct 1 ms 460 KB Output is correct
28 Correct 2 ms 468 KB Output is correct
29 Correct 1 ms 340 KB Output is correct
30 Correct 1 ms 320 KB Output is correct
31 Correct 2 ms 464 KB Output is correct
32 Correct 1 ms 212 KB Output is correct
33 Correct 1 ms 320 KB Output is correct
34 Correct 1 ms 212 KB Output is correct
35 Correct 1 ms 316 KB Output is correct
36 Correct 1 ms 212 KB Output is correct
37 Correct 1 ms 340 KB Output is correct
38 Correct 1 ms 468 KB Output is correct
39 Correct 1 ms 212 KB Output is correct
40 Correct 0 ms 320 KB Output is correct
41 Correct 1 ms 212 KB Output is correct
42 Correct 1 ms 340 KB Output is correct
43 Correct 1 ms 320 KB Output is correct
44 Correct 1 ms 212 KB Output is correct
45 Correct 1 ms 340 KB Output is correct
46 Correct 1 ms 340 KB Output is correct
47 Correct 1 ms 212 KB Output is correct
48 Correct 1 ms 340 KB Output is correct
49 Correct 1 ms 340 KB Output is correct
50 Correct 1 ms 212 KB Output is correct
51 Correct 1 ms 212 KB Output is correct
52 Correct 1 ms 340 KB Output is correct
53 Correct 1 ms 340 KB Output is correct
54 Correct 1 ms 212 KB Output is correct
55 Correct 1 ms 340 KB Output is correct
56 Correct 1 ms 316 KB Output is correct
57 Correct 1 ms 340 KB Output is correct
58 Correct 1 ms 460 KB Output is correct
59 Correct 368 ms 39344 KB Output is correct
60 Correct 441 ms 43360 KB Output is correct
61 Correct 0 ms 212 KB Output is correct
62 Correct 1 ms 320 KB Output is correct
63 Correct 318 ms 34372 KB Output is correct
64 Correct 3 ms 1236 KB Output is correct
65 Correct 12 ms 4208 KB Output is correct
66 Correct 151 ms 33600 KB Output is correct
67 Correct 493 ms 67860 KB Output is correct
68 Correct 494 ms 70252 KB Output is correct
69 Correct 6 ms 1628 KB Output is correct
70 Correct 100 ms 15268 KB Output is correct
71 Correct 319 ms 45816 KB Output is correct
72 Correct 363 ms 44204 KB Output is correct
73 Correct 79 ms 11584 KB Output is correct
74 Correct 457 ms 41076 KB Output is correct
75 Correct 23 ms 5172 KB Output is correct
76 Correct 289 ms 45344 KB Output is correct
77 Correct 309 ms 45552 KB Output is correct
78 Correct 26 ms 7032 KB Output is correct
79 Correct 521 ms 63256 KB Output is correct
80 Correct 2 ms 596 KB Output is correct
81 Correct 120 ms 14820 KB Output is correct
82 Correct 388 ms 43268 KB Output is correct
83 Correct 486 ms 41156 KB Output is correct
84 Correct 451 ms 41188 KB Output is correct
85 Correct 477 ms 41140 KB Output is correct
86 Correct 456 ms 43412 KB Output is correct
87 Correct 486 ms 43424 KB Output is correct