Tietoverkko

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

vector<int> v[101010];

bool z[101010];
int p[101010];

bool found = false;
int f;

void haku(int n, int pp) {
  //cout << n << " :: " << pp << endl;
  if(z[n]) {found = true; f = n; return; }
  z[n] = true;
  p[n] = pp;
  for(int u : v[n]) {
    if(u != pp) haku(u, n);
  }
}

int main() {
  for(int i=0; i < 101010; i++) z[i] = false;
  int n;
  cin >> n;
  for(int i = 0; i < n; i++) {
    int a, b; cin >> a >> b;
    v[a].push_back(b);
    v[b].push_back(a);
  }
  haku(1,1);
  int cc = 1;
  int oc_f = f;
  f = p[f];
  if(found) {
    while(f != oc_f) {
      f = p[f];
      cc++;
    }
    cout << n-cc;
  }
  else cout << n;
}

Test 1

Group: 1

Verdict: TIME LIMIT EXCEEDED

Test 2

Group: 1

Verdict: TIME LIMIT EXCEEDED

Test 3

Group: 1

Verdict: TIME LIMIT EXCEEDED

Test 4

Group: 1

Verdict: TIME LIMIT EXCEEDED

Test 5

Group: 1

Verdict: TIME LIMIT EXCEEDED

Test 6

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 7

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 8

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 9

Group: 2

Verdict: TIME LIMIT EXCEEDED

Test 10

Group: 2

Verdict: TIME LIMIT EXCEEDED