답안 #911534

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
911534	2024-01-19T03:20:59 Z	12345678	Network (BOI15_net)	C++17	100 / 100	732 ms	79368 KB

#include <bits/stdc++.h>

using namespace std;

const int nx=5e5+5;
int n, u, v, st, sz[nx], c, res, lsz;
vector<int> d[nx], l[nx];
priority_queue<pair<int, int>> pq;
vector<pair<int, int>> ans;

int dfssz(int u, int p)
{
    sz[u]=(d[u].size()==1);
    for (auto v:d[u]) if (v!=p) sz[u]+=dfssz(v, u);
    return sz[u];
}

int findcentroid(int u, int p, int rtsz)
{
    for (auto v:d[u]) if (v!=p&&sz[v]*2>rtsz) return findcentroid(v, u, rtsz);
    return u;
}

void dfsadd(int u, int p, vector<int> &x)
{
    if (d[u].size()==1) x.push_back(u);
    for (auto v:d[u]) if (v!=p) dfsadd(v, u, x); 
}

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin>>n;
    for (int i=0; i<n-1; i++) cin>>u>>v, d[u].push_back(v), d[v].push_back(u);
    for (int i=1; i<=n; i++) if (d[i].size()>1) st=i;
    c=findcentroid(st, st, dfssz(st, st));
    for (auto v:d[c]) dfsadd(v, c, l[v]);
    for (auto v:d[c]) pq.push({l[v].size(), v}), lsz+=l[v].size();
    cout<<(lsz+1)/2<<'\n';
    while (!pq.empty())
    {
        if (pq.size()>1)
        {
            auto f=pq.top().second;
            pq.pop();
            auto s=pq.top().second;
            pq.pop();
            ans.push_back({l[f][l[f].size()-1], l[s][l[s].size()-1]});
            l[f].pop_back(); l[s].pop_back();
            if (!l[f].empty()) pq.push({l[f].size(), f});
            if (!l[s].empty()) pq.push({l[s].size(), s});
        }
        else 
        {
            auto f=pq.top().second;
            ans.push_back({c, l[f][0]});
            pq.pop();
        }
    }
    //cout<<ans.size()<<'\n';
    for (auto [x, y]:ans) cout<<x<<' '<<y<<'\n';
}

/*
4
1 3
2 3
3 4
*/

Subtask #1
18.0 / 18.0

#	결과	실행 시간	메모리	Grader output
1	Correct	6 ms	25180 KB	Output is correct
2	Correct	7 ms	25180 KB	Output is correct
3	Correct	6 ms	25180 KB	Output is correct
4	Correct	7 ms	25180 KB	Output is correct
5	Correct	7 ms	25180 KB	Output is correct
6	Correct	7 ms	25176 KB	Output is correct
7	Correct	6 ms	25180 KB	Output is correct
8	Correct	6 ms	25180 KB	Output is correct
9	Correct	7 ms	25176 KB	Output is correct
10	Correct	8 ms	25180 KB	Output is correct
11	Correct	7 ms	25180 KB	Output is correct
12	Correct	6 ms	25180 KB	Output is correct
13	Correct	6 ms	25180 KB	Output is correct
14	Correct	7 ms	25260 KB	Output is correct
15	Correct	7 ms	25180 KB	Output is correct
16	Correct	7 ms	25180 KB	Output is correct
17	Correct	6 ms	25180 KB	Output is correct
18	Correct	7 ms	25008 KB	Output is correct
19	Correct	7 ms	25180 KB	Output is correct
20	Correct	7 ms	25180 KB	Output is correct

Subtask #2
45.0 / 45.0

#	결과	실행 시간	메모리	Grader output
1	Correct	6 ms	25180 KB	Output is correct
2	Correct	7 ms	25180 KB	Output is correct
3	Correct	6 ms	25180 KB	Output is correct
4	Correct	7 ms	25180 KB	Output is correct
5	Correct	7 ms	25180 KB	Output is correct
6	Correct	7 ms	25176 KB	Output is correct
7	Correct	6 ms	25180 KB	Output is correct
8	Correct	6 ms	25180 KB	Output is correct
9	Correct	7 ms	25176 KB	Output is correct
10	Correct	8 ms	25180 KB	Output is correct
11	Correct	7 ms	25180 KB	Output is correct
12	Correct	6 ms	25180 KB	Output is correct
13	Correct	6 ms	25180 KB	Output is correct
14	Correct	7 ms	25260 KB	Output is correct
15	Correct	7 ms	25180 KB	Output is correct
16	Correct	7 ms	25180 KB	Output is correct
17	Correct	6 ms	25180 KB	Output is correct
18	Correct	7 ms	25008 KB	Output is correct
19	Correct	7 ms	25180 KB	Output is correct
20	Correct	7 ms	25180 KB	Output is correct
21	Correct	6 ms	25176 KB	Output is correct
22	Correct	7 ms	25180 KB	Output is correct
23	Correct	9 ms	25436 KB	Output is correct
24	Correct	7 ms	25272 KB	Output is correct
25	Correct	9 ms	25180 KB	Output is correct
26	Correct	8 ms	25180 KB	Output is correct
27	Correct	9 ms	25176 KB	Output is correct
28	Correct	7 ms	25180 KB	Output is correct
29	Correct	8 ms	25180 KB	Output is correct
30	Correct	6 ms	25180 KB	Output is correct
31	Correct	8 ms	25180 KB	Output is correct
32	Correct	7 ms	25180 KB	Output is correct
33	Correct	7 ms	25264 KB	Output is correct
34	Correct	7 ms	25180 KB	Output is correct
35	Correct	7 ms	25180 KB	Output is correct
36	Correct	7 ms	25176 KB	Output is correct
37	Correct	6 ms	25180 KB	Output is correct
38	Correct	7 ms	25180 KB	Output is correct
39	Correct	7 ms	25180 KB	Output is correct
40	Correct	7 ms	25180 KB	Output is correct
41	Correct	6 ms	25180 KB	Output is correct
42	Correct	7 ms	25180 KB	Output is correct
43	Correct	7 ms	25180 KB	Output is correct
44	Correct	7 ms	25180 KB	Output is correct
45	Correct	7 ms	25180 KB	Output is correct
46	Correct	7 ms	25180 KB	Output is correct
47	Correct	6 ms	25180 KB	Output is correct
48	Correct	7 ms	25180 KB	Output is correct
49	Correct	7 ms	25180 KB	Output is correct
50	Correct	7 ms	25012 KB	Output is correct
51	Correct	7 ms	25180 KB	Output is correct
52	Correct	6 ms	25180 KB	Output is correct
53	Correct	6 ms	25180 KB	Output is correct
54	Correct	8 ms	25180 KB	Output is correct
55	Correct	8 ms	25180 KB	Output is correct
56	Correct	6 ms	25180 KB	Output is correct
57	Correct	7 ms	25180 KB	Output is correct
58	Correct	7 ms	25180 KB	Output is correct

Subtask #3
37.0 / 37.0

#	결과	실행 시간	메모리	Grader output
1	Correct	6 ms	25180 KB	Output is correct
2	Correct	7 ms	25180 KB	Output is correct
3	Correct	6 ms	25180 KB	Output is correct
4	Correct	7 ms	25180 KB	Output is correct
5	Correct	7 ms	25180 KB	Output is correct
6	Correct	7 ms	25176 KB	Output is correct
7	Correct	6 ms	25180 KB	Output is correct
8	Correct	6 ms	25180 KB	Output is correct
9	Correct	7 ms	25176 KB	Output is correct
10	Correct	8 ms	25180 KB	Output is correct
11	Correct	7 ms	25180 KB	Output is correct
12	Correct	6 ms	25180 KB	Output is correct
13	Correct	6 ms	25180 KB	Output is correct
14	Correct	7 ms	25260 KB	Output is correct
15	Correct	7 ms	25180 KB	Output is correct
16	Correct	7 ms	25180 KB	Output is correct
17	Correct	6 ms	25180 KB	Output is correct
18	Correct	7 ms	25008 KB	Output is correct
19	Correct	7 ms	25180 KB	Output is correct
20	Correct	7 ms	25180 KB	Output is correct
21	Correct	6 ms	25176 KB	Output is correct
22	Correct	7 ms	25180 KB	Output is correct
23	Correct	9 ms	25436 KB	Output is correct
24	Correct	7 ms	25272 KB	Output is correct
25	Correct	9 ms	25180 KB	Output is correct
26	Correct	8 ms	25180 KB	Output is correct
27	Correct	9 ms	25176 KB	Output is correct
28	Correct	7 ms	25180 KB	Output is correct
29	Correct	8 ms	25180 KB	Output is correct
30	Correct	6 ms	25180 KB	Output is correct
31	Correct	8 ms	25180 KB	Output is correct
32	Correct	7 ms	25180 KB	Output is correct
33	Correct	7 ms	25264 KB	Output is correct
34	Correct	7 ms	25180 KB	Output is correct
35	Correct	7 ms	25180 KB	Output is correct
36	Correct	7 ms	25176 KB	Output is correct
37	Correct	6 ms	25180 KB	Output is correct
38	Correct	7 ms	25180 KB	Output is correct
39	Correct	7 ms	25180 KB	Output is correct
40	Correct	7 ms	25180 KB	Output is correct
41	Correct	6 ms	25180 KB	Output is correct
42	Correct	7 ms	25180 KB	Output is correct
43	Correct	7 ms	25180 KB	Output is correct
44	Correct	7 ms	25180 KB	Output is correct
45	Correct	7 ms	25180 KB	Output is correct
46	Correct	7 ms	25180 KB	Output is correct
47	Correct	6 ms	25180 KB	Output is correct
48	Correct	7 ms	25180 KB	Output is correct
49	Correct	7 ms	25180 KB	Output is correct
50	Correct	7 ms	25012 KB	Output is correct
51	Correct	7 ms	25180 KB	Output is correct
52	Correct	6 ms	25180 KB	Output is correct
53	Correct	6 ms	25180 KB	Output is correct
54	Correct	8 ms	25180 KB	Output is correct
55	Correct	8 ms	25180 KB	Output is correct
56	Correct	6 ms	25180 KB	Output is correct
57	Correct	7 ms	25180 KB	Output is correct
58	Correct	7 ms	25180 KB	Output is correct
59	Correct	420 ms	55488 KB	Output is correct
60	Correct	391 ms	54324 KB	Output is correct
61	Correct	7 ms	25180 KB	Output is correct
62	Correct	7 ms	25376 KB	Output is correct
63	Correct	394 ms	50988 KB	Output is correct
64	Correct	9 ms	25480 KB	Output is correct
65	Correct	16 ms	27228 KB	Output is correct
66	Correct	97 ms	40068 KB	Output is correct
67	Correct	639 ms	79368 KB	Output is correct
68	Correct	732 ms	69744 KB	Output is correct
69	Correct	15 ms	26716 KB	Output is correct
70	Correct	124 ms	40708 KB	Output is correct
71	Correct	557 ms	77116 KB	Output is correct
72	Correct	500 ms	74000 KB	Output is correct
73	Correct	73 ms	32464 KB	Output is correct
74	Correct	546 ms	52512 KB	Output is correct
75	Correct	37 ms	29356 KB	Output is correct
76	Correct	439 ms	65572 KB	Output is correct
77	Correct	462 ms	66248 KB	Output is correct
78	Correct	30 ms	28764 KB	Output is correct
79	Correct	708 ms	62468 KB	Output is correct
80	Correct	10 ms	25432 KB	Output is correct
81	Correct	128 ms	38152 KB	Output is correct
82	Correct	555 ms	63432 KB	Output is correct
83	Correct	495 ms	52468 KB	Output is correct
84	Correct	533 ms	52920 KB	Output is correct
85	Correct	442 ms	53028 KB	Output is correct
86	Correct	396 ms	54760 KB	Output is correct
87	Correct	403 ms	54716 KB	Output is correct

답안 #911534

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