Tietoverkko

input/code.cpp: In function 'void dfs(int, int)':
input/code.cpp:24:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int j = 0; j < graph[i].size(); ++j) {
                   ^
input/code.cpp: In function 'int main()':
input/code.cpp:52:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i < cycle.size(); ++i) {
                   ^
input/code.cpp:63:12: warning: 'size' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout << n - size + 1 << "\n";
            ^

#include <iostream>
#include <vector>

using namespace std;

const int N = 1e5 + 5;

vector<int> graph[N];
vector<int> cycle;


bool seen[N];
bool found;

void dfs(int i, int from) {
	if(found) return;
	if(seen[i]) {
		cycle.push_back(i);
		found = true;
		return;
	}
	seen[i] = true;

	for(int j = 0; j < graph[i].size(); ++j) {
		int k = graph[i][j];
		if(k == from) continue;
		dfs(k, i);
		if(found) break;
	}

	if(found) {
		cycle.push_back(i);
	}



}


int main() {
	int n;
	cin >> n;
	for(int i = 1; i <= n; ++i) {
		int a, b;
		cin >> a >> b;
		graph[a].push_back(b);
		graph[b].push_back(a);
	}

	dfs(1, 0);
	int size;
	for(int i = 0; i < cycle.size(); ++i) {
		if(cycle[i] == cycle[0] && i > 0) {
			//cout << cycle[i] << " ";
			size = i + 1;
			break;
		}
		//cout << cycle[i] << " ";
		size = i+1;
	}
	//cout << "\n";

	cout << n - size + 1 << "\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