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Submission #394618

# Submission time Handle Problem Language Result Execution time Memory
394618 2021-04-27T06:01:24 Z suto Network (BOI15_net) C++17
100 / 100
 539 ms 45768 KB 
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
typedef pair<double, double> pdd;
typedef pair<ld , ll> pdl;
typedef string str;

#define all(x)                      (x).begin(),(x).end()
#define Sort(x)                     sort(all((x)))
#define X                           first
#define Y                           second
#define Mp                          make_pair
#define pb(x)                       push_back(x)
#define pf(x)                       push_front(x)
#define sep                         ' '
#define endl                        '\n'
#define debug(x)                    cerr << #x << " = " << x << endl
#define SZ(x)                       ll(x.size())
#define fast_io                     ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);

const ll MAXN = 5e5 + 10;
const ll INF = 1e18 + 10;
const ll LOG = 1e7 + 19;
const ll MOD = 998244353;

ll pw(ll a , ll b, ll M)  { return (!b ? 1 : (b & 1 ? (a * pw(a * a % M, b / 2, M)) % M : pw(a * a % M, b / 2, M))); }

ll a[MAXN] , mark[MAXN];
vector <ll> adj[MAXN] , barg;

void dfs(ll v){

    mark[v] = 1;
    if(adj[v].size() == 1){
        barg.pb(v);
        return;
    }
    for(auto u: adj[v]){
        if(!mark[u]){
            dfs(u);
        }
    }

}

int main(){

    fast_io;
    ll n;
    cin >> n;
    for(int i = 1; i < n; i++){
        ll v , u;
        cin >> v >> u;
        adj[v].pb(u);
        adj[u].pb(v);
    }
    ll root = 0;
    for(int i = 1; i <= n; i++){
        if(adj[i].size() > 1){
            root = i;
            break;
        }
    }
    dfs(root);
    ll k = barg.size() , p = (k + 1) / 2;
    k /= 2;
    cout << p << endl;
    for(int i = 0; i < p; i++){
        cout << barg[i] << sep << barg[i + k] << endl;
    }

}

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11980 KB Output is correct
2 Correct 8 ms 11980 KB Output is correct
3 Correct 7 ms 11980 KB Output is correct
4 Correct 7 ms 12036 KB Output is correct
5 Correct 7 ms 11980 KB Output is correct
6 Correct 7 ms 11980 KB Output is correct
7 Correct 7 ms 11980 KB Output is correct
8 Correct 7 ms 11980 KB Output is correct
9 Correct 7 ms 11980 KB Output is correct
10 Correct 7 ms 11980 KB Output is correct
11 Correct 7 ms 12064 KB Output is correct
12 Correct 7 ms 12024 KB Output is correct
13 Correct 7 ms 11980 KB Output is correct
14 Correct 8 ms 11980 KB Output is correct
15 Correct 8 ms 11980 KB Output is correct
16 Correct 8 ms 11980 KB Output is correct
17 Correct 8 ms 11980 KB Output is correct
18 Correct 8 ms 11980 KB Output is correct
19 Correct 8 ms 11984 KB Output is correct
20 Correct 8 ms 12056 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11980 KB Output is correct
2 Correct 8 ms 11980 KB Output is correct
3 Correct 7 ms 11980 KB Output is correct
4 Correct 7 ms 12036 KB Output is correct
5 Correct 7 ms 11980 KB Output is correct
6 Correct 7 ms 11980 KB Output is correct
7 Correct 7 ms 11980 KB Output is correct
8 Correct 7 ms 11980 KB Output is correct
9 Correct 7 ms 11980 KB Output is correct
10 Correct 7 ms 11980 KB Output is correct
11 Correct 7 ms 12064 KB Output is correct
12 Correct 7 ms 12024 KB Output is correct
13 Correct 7 ms 11980 KB Output is correct
14 Correct 8 ms 11980 KB Output is correct
15 Correct 8 ms 11980 KB Output is correct
16 Correct 8 ms 11980 KB Output is correct
17 Correct 8 ms 11980 KB Output is correct
18 Correct 8 ms 11980 KB Output is correct
19 Correct 8 ms 11984 KB Output is correct
20 Correct 8 ms 12056 KB Output is correct
21 Correct 7 ms 11972 KB Output is correct
22 Correct 8 ms 12108 KB Output is correct
23 Correct 8 ms 12108 KB Output is correct
24 Correct 8 ms 12108 KB Output is correct
25 Correct 8 ms 12064 KB Output is correct
26 Correct 9 ms 12160 KB Output is correct
27 Correct 9 ms 12108 KB Output is correct
28 Correct 10 ms 12188 KB Output is correct
29 Correct 9 ms 12160 KB Output is correct
30 Correct 8 ms 11980 KB Output is correct
31 Correct 8 ms 12108 KB Output is correct
32 Correct 8 ms 11980 KB Output is correct
33 Correct 8 ms 12064 KB Output is correct
34 Correct 8 ms 12008 KB Output is correct
35 Correct 8 ms 11976 KB Output is correct
36 Correct 8 ms 12056 KB Output is correct
37 Correct 8 ms 11980 KB Output is correct
38 Correct 9 ms 12108 KB Output is correct
39 Correct 7 ms 11980 KB Output is correct
40 Correct 8 ms 11980 KB Output is correct
41 Correct 8 ms 11956 KB Output is correct
42 Correct 8 ms 11980 KB Output is correct
43 Correct 8 ms 12108 KB Output is correct
44 Correct 8 ms 11980 KB Output is correct
45 Correct 8 ms 12048 KB Output is correct
46 Correct 8 ms 12084 KB Output is correct
47 Correct 8 ms 11956 KB Output is correct
48 Correct 8 ms 11980 KB Output is correct
49 Correct 8 ms 12108 KB Output is correct
50 Correct 8 ms 11980 KB Output is correct
51 Correct 8 ms 11980 KB Output is correct
52 Correct 8 ms 11980 KB Output is correct
53 Correct 8 ms 12108 KB Output is correct
54 Correct 7 ms 11980 KB Output is correct
55 Correct 10 ms 11980 KB Output is correct
56 Correct 8 ms 11980 KB Output is correct
57 Correct 8 ms 12080 KB Output is correct
58 Correct 9 ms 12108 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11980 KB Output is correct
2 Correct 8 ms 11980 KB Output is correct
3 Correct 7 ms 11980 KB Output is correct
4 Correct 7 ms 12036 KB Output is correct
5 Correct 7 ms 11980 KB Output is correct
6 Correct 7 ms 11980 KB Output is correct
7 Correct 7 ms 11980 KB Output is correct
8 Correct 7 ms 11980 KB Output is correct
9 Correct 7 ms 11980 KB Output is correct
10 Correct 7 ms 11980 KB Output is correct
11 Correct 7 ms 12064 KB Output is correct
12 Correct 7 ms 12024 KB Output is correct
13 Correct 7 ms 11980 KB Output is correct
14 Correct 8 ms 11980 KB Output is correct
15 Correct 8 ms 11980 KB Output is correct
16 Correct 8 ms 11980 KB Output is correct
17 Correct 8 ms 11980 KB Output is correct
18 Correct 8 ms 11980 KB Output is correct
19 Correct 8 ms 11984 KB Output is correct
20 Correct 8 ms 12056 KB Output is correct
21 Correct 7 ms 11972 KB Output is correct
22 Correct 8 ms 12108 KB Output is correct
23 Correct 8 ms 12108 KB Output is correct
24 Correct 8 ms 12108 KB Output is correct
25 Correct 8 ms 12064 KB Output is correct
26 Correct 9 ms 12160 KB Output is correct
27 Correct 9 ms 12108 KB Output is correct
28 Correct 10 ms 12188 KB Output is correct
29 Correct 9 ms 12160 KB Output is correct
30 Correct 8 ms 11980 KB Output is correct
31 Correct 8 ms 12108 KB Output is correct
32 Correct 8 ms 11980 KB Output is correct
33 Correct 8 ms 12064 KB Output is correct
34 Correct 8 ms 12008 KB Output is correct
35 Correct 8 ms 11976 KB Output is correct
36 Correct 8 ms 12056 KB Output is correct
37 Correct 8 ms 11980 KB Output is correct
38 Correct 9 ms 12108 KB Output is correct
39 Correct 7 ms 11980 KB Output is correct
40 Correct 8 ms 11980 KB Output is correct
41 Correct 8 ms 11956 KB Output is correct
42 Correct 8 ms 11980 KB Output is correct
43 Correct 8 ms 12108 KB Output is correct
44 Correct 8 ms 11980 KB Output is correct
45 Correct 8 ms 12048 KB Output is correct
46 Correct 8 ms 12084 KB Output is correct
47 Correct 8 ms 11956 KB Output is correct
48 Correct 8 ms 11980 KB Output is correct
49 Correct 8 ms 12108 KB Output is correct
50 Correct 8 ms 11980 KB Output is correct
51 Correct 8 ms 11980 KB Output is correct
52 Correct 8 ms 11980 KB Output is correct
53 Correct 8 ms 12108 KB Output is correct
54 Correct 7 ms 11980 KB Output is correct
55 Correct 10 ms 11980 KB Output is correct
56 Correct 8 ms 11980 KB Output is correct
57 Correct 8 ms 12080 KB Output is correct
58 Correct 9 ms 12108 KB Output is correct
59 Correct 355 ms 38076 KB Output is correct
60 Correct 431 ms 40620 KB Output is correct
61 Correct 7 ms 11980 KB Output is correct
62 Correct 7 ms 11980 KB Output is correct
63 Correct 311 ms 34640 KB Output is correct
64 Correct 9 ms 12364 KB Output is correct
65 Correct 18 ms 13860 KB Output is correct
66 Correct 140 ms 26952 KB Output is correct
67 Correct 539 ms 44340 KB Output is correct
68 Correct 485 ms 45768 KB Output is correct
69 Correct 13 ms 13004 KB Output is correct
70 Correct 86 ms 22516 KB Output is correct
71 Correct 320 ms 43048 KB Output is correct
72 Correct 322 ms 41888 KB Output is correct
73 Correct 94 ms 19464 KB Output is correct
74 Correct 453 ms 38456 KB Output is correct
75 Correct 30 ms 15420 KB Output is correct
76 Correct 316 ms 42568 KB Output is correct
77 Correct 314 ms 43056 KB Output is correct
78 Correct 43 ms 15684 KB Output is correct
79 Correct 514 ms 42452 KB Output is correct
80 Correct 9 ms 12236 KB Output is correct
81 Correct 112 ms 21776 KB Output is correct
82 Correct 384 ms 40676 KB Output is correct
83 Correct 453 ms 38456 KB Output is correct
84 Correct 452 ms 38412 KB Output is correct
85 Correct 455 ms 38364 KB Output is correct
86 Correct 426 ms 40748 KB Output is correct
87 Correct 469 ms 40592 KB Output is correct