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ID	Problem	Submitter	Result	Time	Memory	Language	File size	Submit time	Judge time
#221413	#3846. Link-Cut Tree	BUET_POTATOES^#	AC ✓	568ms	24608kb	C++20	2.2kb	2023-10-21 13:15:48	2023-10-21 13:15:49

Judging History

你现在查看的是最新测评结果

[2023-10-21 13:15:49]
评测

测评结果：AC
用时：568ms
内存：24608kb

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[2023-10-21 13:15:48]
提交

answer

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

const int N = 1e5 + 5;

int p[N];
int vis[N];
vector<int> adj[N];
map<pair<int, int>, int>mp;
int f(int ind){
    return p[ind] = (p[ind] == ind ? ind : f(p[ind]));
}

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

    int tc;
    cin>>tc;

    for(int cs = 1; cs <= tc; cs++){
        int n, m;
        cin >> n >> m;
        mp.clear();
        for(int i = 1; i <= n; i++){
            adj[i].clear();
            p[i] = i;
            vis[i] = 0;
        }
        bool done = false;
        int root;
        for(int i = 1; i <= m; i++){
            int u, v;
            cin >> u >> v;
            if(done == false){
                adj[u].push_back(v);
                adj[v].push_back(u);
                mp[{u, v}] = i;
                mp[{v, u}] = i;
            }
            u = f(u);
            v = f(v);
            if(u == v && done == false){
                done = true;
                root = u;
            }
            p[u] = v;
        }
        if(done == false){
            cout << -1 << "\n";
            continue;
        }
        vector<int> ans;
        vector<int> st;
        auto dfs = [&](auto &&dfs, int u, int par){
            vis[u] = 1;
            st.push_back(u);
            for(auto x : adj[u]){
                if(x == par)continue;
                if(vis[x] == 1){
                    for(int i = 0; i < st.size(); i++){
                        ans.push_back(st[st.size() - i - 1]);
                        if(st[st.size() - i - 1] == x)break;
                    }
                    return true;
                }
                if(dfs(dfs, x, u))return true;
            }
            st.pop_back();
            return false;
        };

        dfs(dfs, root, -1);
        vector<int> temp;
        for(int i = 0; i < ans.size(); i++){
            temp.push_back(mp[{ans[i], ans[(i + 1) % ans.size()]}]);
        }
        sort(temp.begin(), temp.end());
        for(int i = 0; i < temp.size(); i++){
            if(i)cout << ' ';
            cout << temp[i];
        }
        cout << "\n";


    }

    return 0;
}

Source code, Language: C++20

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100

Accepted

time: 1ms

memory: 5968kb

input:

output:

2 4 5 6
-1

result:

ok 2 lines

Test #2:

score: 0

Accepted

time: 568ms

memory: 22768kb

input:

output:

2 5 8
3 5 7
1 3 4
2 3 4
2 3 4 7 13
1 3 4 5 9
3 4 7 12
1 2 3
8 10 11
2 3 5 7 12 13 14 15 16
1 2 3 5
1 2 4
1 3 4
1 2 3
1 2 3
10 11 15
1 5 6
1 5 7
1 2 3 4
-1
1 3 6
-1
1 2 3 5
-1
-1
6 8 9 10 11 16
1 2 6
2 3 4
-1
-1
7 8 12 13 18
-1
1 4 8 12
3 5 10
4 6 8
1 2 3 4
3 5 6
5 8 10 15
4 6 8
-1
1 2 3 5 6
1 3 4
1 ...

result:

ok 1658 lines

Test #3:

score: 0

Accepted

time: 438ms

memory: 24608kb

input:

10
100000 100000
1 2
2 3
3 4
4 5
5 6
6 7
7 8
8 9
9 10
10 11
11 12
12 13
13 14
14 15
15 16
16 17
17 18
18 19
19 20
20 21
21 22
22 23
23 24
24 25
25 26
26 27
27 28
28 29
29 30
30 31
31 32
32 33
33 34
34 35
35 36
36 37
37 38
38 39
39 40
40 41
41 42
42 43
43 44
44 45
45 46
46 47
47 48
48 49
49 50
50 51
...

output:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 ...

result:

ok 10 lines