Tunnels

#include <bits/stdc++.h>
#define llong long long
#define f first
#define s second
#define mp make_pair
//#define cin fin

using namespace::std;

ifstream fin("input.txt");

int MAXS = 1e5 + 5;
int answ = 0;

vector<bool> visited(MAXS);
vector<vector<int> > adj(MAXS, vector<int>(0));
vector<pair<int, int> > inout(MAXS);

void dfs(int st)
{
    queue<int> Q;
    Q.push(st);
    visited[st] = 1;
    int cur, val = 0;

    while (!Q.empty()) {
        cur = Q.front(); Q.pop();
        val += abs(inout[cur].f - inout[cur].s);

        for (auto i : adj[cur]) {
            if (visited[i] == 0) {
                visited[i] = 1;
                Q.push(i);
            }
        }
    }
    //val = max(val / 2, 1);
    answ += val / 2;
}


int main()
{
    int n, m, t1, t2;
    cin >> n >> m;
    for (int i = 0; i < m; i++) {
        cin >> t1 >> t2;
        adj[t1].push_back(t2);
        adj[t2].push_back(t1);
        inout[t1].f++;
        inout[t2].s++;
    }

    for (int i = 1; i <= n; i++) {
        if (visited[i] == 0) {
            //cout << i << "\n";
            dfs(i);
        }
    }
    cout << answ << "\n";

    //system("pause");
}

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

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED