func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, m;     cin >> n >> m;     int* degree = new int[100005];     for (int i = 1; i <= n; i++) {       degree[i] = 0;     }     while (m--) {       int a, b;       cin >> a >> b;       degree[a]++;       degree[b]++;     }     int deg1 = 0, deg2 = 0, degG = 0;     for (int i = 1; i <= n; i++) {       if (degree[i] == 0) {         continue;       } else if (degree[i] == 1) {         deg1++;       } else if (degree[i] == 2) {         deg2++;       } else if (degree[i] == n - 1) {         degG++;       }     }     if (deg1 == n - 1 && deg2 == 0 && degG == 1) {       cout <<  star topology ;       return 0;     } else if (deg1 == 2 && deg2 == n - 2 && degG == 0) {       cout <<  bus topology ;       return 0;     } else if (deg1 == 0 && deg2 == n && degG == 0) {       cout <<  ring topology ;       return 0;     } else {       cout <<  unknown topology ;     }     return 0;   }   