답안 #113186

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
113186	2019-05-24T08:09:29 Z	Abelyan	Network (BOI15_net)	C++17	100 / 100	832 ms	78280 KB

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

#define FOR(i,a) for (int i=0;i<(a);++i)
#define FORD(i,a) for (int i=(a)-1;i>=0;i--)
#define FORT(i,a,b) for (int i=(a);i<=(b);++i)
#define FORTD(i,b,a) for (int i=(b);i>=(a);--i)
#define trav(i,v) for (auto i : v)
#define all(v) v.begin(),v.end()
#define ad push_back
#define fr first
#define sc second
#define mpr(a,b) make_pair(a,b)
#define pir pair<int,int>
#define all(v) v.begin(),v.end()
#define make_unique(v) v.erase(unique(all(v),v.end()))
#define fastio ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define dbg(x);
#define dbgv(v);
#define srng mt19937 rng(chrono::steady_clock::now().time_since_epoch().count())
#define y1 EsiHancagorcRepa
#ifdef ALEXPC
#define dbg(x); cout<<#x<<" = "<<x<<endl
#define dbgv(v); cout<<#v<<" = ["; trav(tv,v)cout<<"tv,";cout<<"]"<<endl
#endif

//const int N=100,M=N*N;
const ll MOD=1000*1000*1000+7;

const int N=2*1e6+6,M=6*N,MAXND=N;
const ll MX=1000000000ll*1000000000ll;

int n,d[N];
vector<int> g[N];
vector<int> ans;

void dfs(int v,int par=-1){
    if (d[v]==1){
        ans.push_back(v);
        return;
    }
    trav(to,g[v])if (to!=par)dfs(to,v);
}
int main(){
    fastio;
    srng;
    cin>>n;
    FOR(i,n-1){
        int a,b;
        cin>>a>>b;
        d[a]++;
        d[b]++;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    FORT(i,1,n){
        if (d[i]!=1){
            dfs(i);
            break;
        }
    }
    int k;
    if (ans.size()%2)k=ans.size()/2+1;
    else k=ans.size()/2;
    cout<<k<<endl;
    FOR(i,k){
        if (i+k==ans.size()){
            cout<<ans[i]<<" "<<ans.back()<<endl;
        }
        else cout<<ans[i]<<" "<<ans[i+k]<<endl;
    }
    return 0;
}
/*
3 4
1 2 5
2 3 2
3 1 4
2 3 8
5
2 1 5
2 1 2
2 2 5
2 3 4
2 3 2
*/

Compilation message

net.cpp: In function 'int main()':
net.cpp:71:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if (i+k==ans.size()){
             ~~~^~~~~~~~~~~~

Subtask #1
18.0 / 18.0

#	결과	실행 시간	메모리	Grader output
1	Correct	43 ms	47352 KB	Output is correct
2	Correct	48 ms	47480 KB	Output is correct
3	Correct	41 ms	47352 KB	Output is correct
4	Correct	41 ms	47224 KB	Output is correct
5	Correct	41 ms	47356 KB	Output is correct
6	Correct	41 ms	47352 KB	Output is correct
7	Correct	41 ms	47352 KB	Output is correct
8	Correct	51 ms	47356 KB	Output is correct
9	Correct	49 ms	47352 KB	Output is correct
10	Correct	41 ms	47352 KB	Output is correct
11	Correct	40 ms	47352 KB	Output is correct
12	Correct	41 ms	47360 KB	Output is correct
13	Correct	40 ms	47332 KB	Output is correct
14	Correct	40 ms	47352 KB	Output is correct
15	Correct	40 ms	47352 KB	Output is correct
16	Correct	40 ms	47356 KB	Output is correct
17	Correct	41 ms	47352 KB	Output is correct
18	Correct	39 ms	47312 KB	Output is correct
19	Correct	39 ms	47352 KB	Output is correct
20	Correct	40 ms	47224 KB	Output is correct

Subtask #2
45.0 / 45.0

#	결과	실행 시간	메모리	Grader output
1	Correct	43 ms	47352 KB	Output is correct
2	Correct	48 ms	47480 KB	Output is correct
3	Correct	41 ms	47352 KB	Output is correct
4	Correct	41 ms	47224 KB	Output is correct
5	Correct	41 ms	47356 KB	Output is correct
6	Correct	41 ms	47352 KB	Output is correct
7	Correct	41 ms	47352 KB	Output is correct
8	Correct	51 ms	47356 KB	Output is correct
9	Correct	49 ms	47352 KB	Output is correct
10	Correct	41 ms	47352 KB	Output is correct
11	Correct	40 ms	47352 KB	Output is correct
12	Correct	41 ms	47360 KB	Output is correct
13	Correct	40 ms	47332 KB	Output is correct
14	Correct	40 ms	47352 KB	Output is correct
15	Correct	40 ms	47352 KB	Output is correct
16	Correct	40 ms	47356 KB	Output is correct
17	Correct	41 ms	47352 KB	Output is correct
18	Correct	39 ms	47312 KB	Output is correct
19	Correct	39 ms	47352 KB	Output is correct
20	Correct	40 ms	47224 KB	Output is correct
21	Correct	41 ms	47352 KB	Output is correct
22	Correct	42 ms	47480 KB	Output is correct
23	Correct	41 ms	47460 KB	Output is correct
24	Correct	42 ms	47484 KB	Output is correct
25	Correct	42 ms	47480 KB	Output is correct
26	Correct	41 ms	47360 KB	Output is correct
27	Correct	42 ms	47480 KB	Output is correct
28	Correct	40 ms	47480 KB	Output is correct
29	Correct	41 ms	47352 KB	Output is correct
30	Correct	40 ms	47352 KB	Output is correct
31	Correct	41 ms	47488 KB	Output is correct
32	Correct	40 ms	47324 KB	Output is correct
33	Correct	41 ms	47352 KB	Output is correct
34	Correct	39 ms	47352 KB	Output is correct
35	Correct	40 ms	47352 KB	Output is correct
36	Correct	40 ms	47352 KB	Output is correct
37	Correct	39 ms	47352 KB	Output is correct
38	Correct	40 ms	47352 KB	Output is correct
39	Correct	41 ms	47276 KB	Output is correct
40	Correct	43 ms	47352 KB	Output is correct
41	Correct	107 ms	47324 KB	Output is correct
42	Correct	41 ms	47324 KB	Output is correct
43	Correct	41 ms	47352 KB	Output is correct
44	Correct	40 ms	47224 KB	Output is correct
45	Correct	42 ms	47352 KB	Output is correct
46	Correct	42 ms	47352 KB	Output is correct
47	Correct	42 ms	47360 KB	Output is correct
48	Correct	41 ms	47352 KB	Output is correct
49	Correct	40 ms	47352 KB	Output is correct
50	Correct	40 ms	47352 KB	Output is correct
51	Correct	39 ms	47356 KB	Output is correct
52	Correct	39 ms	47352 KB	Output is correct
53	Correct	39 ms	47352 KB	Output is correct
54	Correct	40 ms	47360 KB	Output is correct
55	Correct	40 ms	47360 KB	Output is correct
56	Correct	41 ms	47352 KB	Output is correct
57	Correct	42 ms	47332 KB	Output is correct
58	Correct	41 ms	47488 KB	Output is correct

Subtask #3
37.0 / 37.0

#	결과	실행 시간	메모리	Grader output
1	Correct	43 ms	47352 KB	Output is correct
2	Correct	48 ms	47480 KB	Output is correct
3	Correct	41 ms	47352 KB	Output is correct
4	Correct	41 ms	47224 KB	Output is correct
5	Correct	41 ms	47356 KB	Output is correct
6	Correct	41 ms	47352 KB	Output is correct
7	Correct	41 ms	47352 KB	Output is correct
8	Correct	51 ms	47356 KB	Output is correct
9	Correct	49 ms	47352 KB	Output is correct
10	Correct	41 ms	47352 KB	Output is correct
11	Correct	40 ms	47352 KB	Output is correct
12	Correct	41 ms	47360 KB	Output is correct
13	Correct	40 ms	47332 KB	Output is correct
14	Correct	40 ms	47352 KB	Output is correct
15	Correct	40 ms	47352 KB	Output is correct
16	Correct	40 ms	47356 KB	Output is correct
17	Correct	41 ms	47352 KB	Output is correct
18	Correct	39 ms	47312 KB	Output is correct
19	Correct	39 ms	47352 KB	Output is correct
20	Correct	40 ms	47224 KB	Output is correct
21	Correct	41 ms	47352 KB	Output is correct
22	Correct	42 ms	47480 KB	Output is correct
23	Correct	41 ms	47460 KB	Output is correct
24	Correct	42 ms	47484 KB	Output is correct
25	Correct	42 ms	47480 KB	Output is correct
26	Correct	41 ms	47360 KB	Output is correct
27	Correct	42 ms	47480 KB	Output is correct
28	Correct	40 ms	47480 KB	Output is correct
29	Correct	41 ms	47352 KB	Output is correct
30	Correct	40 ms	47352 KB	Output is correct
31	Correct	41 ms	47488 KB	Output is correct
32	Correct	40 ms	47324 KB	Output is correct
33	Correct	41 ms	47352 KB	Output is correct
34	Correct	39 ms	47352 KB	Output is correct
35	Correct	40 ms	47352 KB	Output is correct
36	Correct	40 ms	47352 KB	Output is correct
37	Correct	39 ms	47352 KB	Output is correct
38	Correct	40 ms	47352 KB	Output is correct
39	Correct	41 ms	47276 KB	Output is correct
40	Correct	43 ms	47352 KB	Output is correct
41	Correct	107 ms	47324 KB	Output is correct
42	Correct	41 ms	47324 KB	Output is correct
43	Correct	41 ms	47352 KB	Output is correct
44	Correct	40 ms	47224 KB	Output is correct
45	Correct	42 ms	47352 KB	Output is correct
46	Correct	42 ms	47352 KB	Output is correct
47	Correct	42 ms	47360 KB	Output is correct
48	Correct	41 ms	47352 KB	Output is correct
49	Correct	40 ms	47352 KB	Output is correct
50	Correct	40 ms	47352 KB	Output is correct
51	Correct	39 ms	47356 KB	Output is correct
52	Correct	39 ms	47352 KB	Output is correct
53	Correct	39 ms	47352 KB	Output is correct
54	Correct	40 ms	47360 KB	Output is correct
55	Correct	40 ms	47360 KB	Output is correct
56	Correct	41 ms	47352 KB	Output is correct
57	Correct	42 ms	47332 KB	Output is correct
58	Correct	41 ms	47488 KB	Output is correct
59	Correct	588 ms	67176 KB	Output is correct
60	Correct	832 ms	69480 KB	Output is correct
61	Correct	40 ms	47360 KB	Output is correct
62	Correct	41 ms	47480 KB	Output is correct
63	Correct	543 ms	65188 KB	Output is correct
64	Correct	42 ms	47736 KB	Output is correct
65	Correct	58 ms	49016 KB	Output is correct
66	Correct	233 ms	61688 KB	Output is correct
67	Correct	640 ms	77460 KB	Output is correct
68	Correct	653 ms	78280 KB	Output is correct
69	Correct	59 ms	48120 KB	Output is correct
70	Correct	247 ms	55140 KB	Output is correct
71	Correct	669 ms	72416 KB	Output is correct
72	Correct	684 ms	71652 KB	Output is correct
73	Correct	186 ms	53236 KB	Output is correct
74	Correct	760 ms	68284 KB	Output is correct
75	Correct	94 ms	50168 KB	Output is correct
76	Correct	641 ms	72060 KB	Output is correct
77	Correct	661 ms	72524 KB	Output is correct
78	Correct	74 ms	50428 KB	Output is correct
79	Correct	608 ms	75876 KB	Output is correct
80	Correct	43 ms	47480 KB	Output is correct
81	Correct	222 ms	55132 KB	Output is correct
82	Correct	739 ms	70372 KB	Output is correct
83	Correct	706 ms	68372 KB	Output is correct
84	Correct	716 ms	68208 KB	Output is correct
85	Correct	704 ms	68356 KB	Output is correct
86	Correct	738 ms	69540 KB	Output is correct
87	Correct	750 ms	69452 KB	Output is correct

답안 #113186

Compilation message

Subtask #1 18.0 / 18.0

Subtask #2 45.0 / 45.0

Subtask #3 37.0 / 37.0

Subtask #1
18.0 / 18.0

Subtask #2
45.0 / 45.0

Subtask #3
37.0 / 37.0