while True:
try:
x = input()
n, m = list(map(int, x.split()))
freqs = {(i+1): 0 for i in range(n)}
for i in range(m):
x = input()
a, b = list(map(int, x.split()))
freqs[a] += 1
freqs[b] += 1
freq = {}
for key, val in freqs.items():
if val not in freq:
freq[val] = 1
else:
freq[val] += 1
if len(freq) == 2:
if 1 in freq.keys():
if freq[1] == 2:
print("bus topology")
elif freq[1] == n - 1:
print("star topology")
else:
print("unknown topology")
else:
print("unknown topology")
elif len(freq) == 1:
if 2 in freq.keys():
print("ring topology")
elif 1 in freq.keys():
print("bus topology")
else:
print("unknown topology")
else:
print("unknown topology")
except EOFError:
break
#include "bits/stdc++.h"
using namespace std;
#define int long long
#define pb push_back
#define ppb pop_back
#define pf push_front
#define ppf pop_front
#define all(x) (x).begin(),(x).end()
#define uniq(v) (v).erase(unique(all(v)),(v).end())
#define sz(x) (int)((x).size())
#define fr first
#define sc second
#define pii pair<int,int>
#define rep(i,a,b) for(int i=a;i<b;i++)
#define mem1(a) memset(a,-1,sizeof(a))
#define mem0(a) memset(a,0,sizeof(a))
#define ppc __builtin_popcount
#define ppcll __builtin_popcountll
template<typename T1, typename T2>istream& operator>>(istream& in, pair<T1, T2> &a) {in >> a.fr >> a.sc; return in;}
template<typename T1, typename T2>ostream& operator<<(ostream& out, pair<T1, T2> a) {out << a.fr << " " << a.sc; return out;}
template<typename T, typename T1>T amax(T &a, T1 b) {if (b > a)a = b; return a;}
template<typename T, typename T1>T amin(T &a, T1 b) {if (b < a)a = b; return a;}
const long long INF = 1e18;
const int32_t M = 1e9 + 7;
const int32_t MM = 998244353;
const int N = 1e6 + 7;
const int MOD = 1e9 + 7;
const long long MOD2 = static_cast<long long>(MOD) * MOD;
/* ----------------------------------------------------------------------------------------------------------*/
void solve() {
int n, m, u, v;
cin >> n >> m;
int degree[n + 1];
for (int i = 1; i <= n; i++) {
degree[i] = 0;
}
for (int i = 1; i <= m; i++) {
cin >> u >> v;
degree[u]++;
degree[v]++;
}
int cnt1 = 0, cnt2 = 0, cntN = 0;
for (int i = 1; i <= n; i++) {
if (degree[i] == 1) {
cnt1++;
}
if (degree[i] == 2) {
cnt2++;
}
if (degree[i] == (n - 1)) {
cntN++;
}
}
if (cnt2 == n) {
cout << "ring topology";
return;
}
if (cnt2 == (n - 2) && cnt1 == 2) {
cout << "bus topology";
return;
}
if (cntN == 1 && cnt1 == (n - 1)) {
cout << "star topology";
return;
}
cout << "unknown topology";
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
//freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);
#ifdef SIEVE
sieve();
#endif
#ifdef NCR
init();
#endif
int t = 1;
// cin >> t;
while (t--) solve();
return 0;
}
1607A - Linear Keyboard | EQUALCOIN Equal Coins |
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1084A - The Fair Nut and Elevator | 1440B - Sum of Medians |
1032A - Kitchen Utensils | 1501B - Napoleon Cake |
1584B - Coloring Rectangles | 1562B - Scenes From a Memory |
1521A - Nastia and Nearly Good Numbers | 208. Implement Trie |
1605B - Reverse Sort | 1607C - Minimum Extraction |
1604B - XOR Specia-LIS-t | 1606B - Update Files |
1598B - Groups | 1602B - Divine Array |
1594B - Special Numbers | 1614A - Divan and a Store |
2085. Count Common Words With One Occurrence | 2089. Find Target Indices After Sorting Array |