Submission #10347107

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;

#define rep(i, n) for(int i = 0; i < (int)n; ++i)
#define FOR(i, a, b) for(int i = a; i < (int)b; ++i)
#define rrep(i, n) for(int i = ((int)n - 1); i >= 0; --i)

typedef long long ll;
typedef long double ld;

const ll Inf = 1e18;
const double EPS = 1e-9;
const int MOD = 1e9 + 7;

vector<vector<int> > g;
vector<int> a, b;
vector<bool> visited;

void dfs(int s = 0) {
    visited[s] = true;
    rep (i, g[s].size()) {
        if (!g[s][i]) continue;
        if (visited[i]) continue;
        dfs(i);
    }
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(0);
    int n, m;
    cin >> n >> m;
    g.resize(n), visited.resize(n);
    rep (i, n) g[i].resize(n);
    a.resize(m), b.resize(m);
    rep (i, m) {
        cin >> a[i] >> b[i];
        a[i]--, b[i]--;
        g[a[i]][b[i]] = g[b[i]][a[i]] = true;
    }
    int res = 0;
    rep (i, m) {
        rep (j, n) visited[j] = false;
        g[a[i]][b[i]] = g[b[i]][a[i]] = false;
        dfs();
        bool ok = true;
        rep (i, n) if (!visited[i]) ok = false;
        if (!ok) res++;
        g[a[i]][b[i]] = g[b[i]][a[i]] = true;
    }
    cout << res << endl;
    
    return 0;
}

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