Tietoverkko

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
ll n;
int main() {
	cin >> n;
	set<ll> y[n];
	for (int i=0; i<n; i++) {
		ll a,b;
		cin >> a >> b;
		a--; b--;
		y[a].insert(b);
		y[b].insert(a);
	}
	ll c=0;
	bool jatka = true;
	while (jatka) {
		jatka = false;
		for (int i=0; i<n; i++) {
			if (y[i].size() == 1) {
				int k=*y[i].begin();
				y[k].erase(y[k].find(i));
				y[i].clear();
				c++;
				jatka = true;
			}
		}
	}
	cout << c << "\n";
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED