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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#785378#6421. Degree of Spanning TreelfyszyWA 178ms9676kbC++142.0kb2024-11-26 17:42:462024-11-26 17:42:51

Judging History

你现在查看的是最新测评结果

  • [2024-11-26 17:42:51]
  • 评测
  • 测评结果:WA
  • 用时:178ms
  • 内存:9676kb
  • [2024-11-26 17:42:46]
  • 提交

answer

#include <bits/stdc++.h>
#define int long long
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)
#define SP << " " <<
#define fish signed
using namespace std;
mt19937 rnd(1209);
const int INF = 0x3f3f3f3f3f3f3f3f;
const int N = 1e5 + 10;
vector<pair<int, int>> g;
vector<int> e[N];
int fa[N], fa1[N], d[N];
int find(int x) {return fa[x] == x ? x : fa[x] = find(fa[x]);}
set<pair<int, int>> edge;
void dfs(int u, int f)
{
    fa1[u] = f; if(f) edge.insert({u, f});
    for(auto v : e[u]) if(v != f) dfs(v, u);
}
void solve()
{
    int n, m; cin >> n >> m;
    for(int i = 1; i <= n; i ++) fa[i] = i, d[i] = 0, e[i].clear();
    g.clear(); edge.clear();
    for(int i = 1; i <= m; i ++)
    {
        int u, v; cin >> u >> v;
        int fu = find(u), fv = find(v);
        if(fu != fv)
        {
            fa[fu] = fv;
            e[u].push_back(v), e[v].push_back(u);
            d[u] ++, d[v] ++;
        }
        else g.push_back({u, v});
    }
    int rt = 0;
    for(int i = 1; i <= n; i ++) if(d[i] > d[rt]) rt = i;
    dfs(rt, 0);
    for(int i = 1; i <= n; i ++) if(fa1[i] != rt) fa[i] = fa1[i]; else fa[i] = i;
    for(auto x : g)
    {
        if(d[rt] <= n / 2) break;
        int u = x.first, v = x.second;
        int fu = find(u), fv = find(v);
        if(fu == fv) continue;
        if(d[fu] > d[fv]) swap(fu, fv), swap(u, v);
        if(d[u] + 1 > n / 2 || d[v] + 1 > n / 2) continue;
        edge.erase({fv, rt});
        edge.insert({v, u});
        fa[fv] = fu;
        d[u] ++, d[v] ++, d[fv] --, d[rt] --;
    }
    rt = 0;
    for(int i = 1; i <= n; i ++) if(d[i] > d[rt]) rt = i;
    if(d[rt] <= n / 2)
    {
        cout << "Yes\n";
        assert(edge.size() <= n - 1);
        for(auto v : edge) cout << v.first SP v.second << "\n";
    }
    else cout << "No\n";
}
fish main()
{
    // freopen(".in", "r", stdin);
    // freopen(".out", "w", stdout);
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int t; cin >> t;
    while(t --) solve();
    return 0;
}

詳細信息

Test #1:

score: 100
Accepted
time: 1ms
memory: 8240kb

input:

2
6 9
1 2
1 3
1 4
2 3
2 4
3 4
4 5
4 6
4 6
3 4
1 3
2 3
3 3
1 2

output:

Yes
2 1
3 1
4 1
5 4
6 4
No

result:

ok 2 cases

Test #2:

score: -100
Wrong Answer
time: 178ms
memory: 9676kb

input:

11140
10 15
9 6
5 7
6 5
2 3
7 5
7 5
3 10
9 7
5 5
9 1
7 5
2 8
7 5
4 3
6 2
9 19
3 7
3 9
2 8
2 8
3 6
5 1
1 8
8 9
8 3
4 8
5 5
3 1
4 3
1 3
8 6
1 3
7 4
4 3
8 8
12 20
10 2
5 5
2 4
3 3
3 3
5 11
9 2
5 5
7 12
11 3
3 3
3 5
5 3
3 1
4 6
7 11
6 8
4 5
6 12
6 5
8 18
4 2
4 3
2 4
2 4
4 3
4 8
2 2
6 7
2 4
6 2
1 4
8 7
4...

output:

Yes
1 9
3 2
4 3
5 6
6 2
7 5
8 2
9 6
10 3
Yes
1 8
2 8
3 9
4 8
5 1
6 3
7 3
9 8
Yes
1 3
3 11
4 2
5 4
6 4
7 11
8 6
9 2
10 2
11 5
12 7
Yes
1 4
2 4
3 4
5 7
6 2
7 6
8 4
Yes
1 5
2 9
3 2
4 3
6 5
7 5
8 7
9 5
Yes
1 6
3 2
4 6
5 2
6 2
7 1
8 10
9 1
10 2
Yes
1 7
2 6
3 1
4 5
5 7
6 7
Yes
2 6
3 12
4 1
5 4
6 1
7 8
8 2...

result:

wrong answer case 120, participant does not find a solution but the jury does