Submission #8878035

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Source Code Expand

#include <iostream>
#include <iomanip>
#include <cmath>
#include <string>
#include <vector>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <queue>
#include <numeric>
#include <random>
#include <algorithm>
#include <functional>

using namespace std;
typedef long long ll;

template<class T> inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template<class T> inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}

const int INF = (1 << 30) - 1;
const ll INFLL= (1LL << 61) - 1;
const int MOD = 1000000007;
#define ALL(a) (a).begin(),(a).end()
#define rALL(a) (a).rbegin(),(a).rend()
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)

void dfs(int now, int N, vector<bool> &seen, vector<vector<bool>> &graph){
  seen[now]=true;
  REP(i,N){
    if(graph[now][i] && !seen[i]){
      dfs(i, N, seen, graph);
    };
  }
}

int main(){
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  int N,M,ans=0;
  cin>>N>>M;
  vector<vector<bool>> graph(N,vector<bool>(N));
  vector<int>a(M),b(M);
  REP(i,M){
    cin>>a[i]>>b[i];
    a[i]--;b[i]--;
    graph[a[i]][b[i]]=true;
    graph[b[i]][a[i]]=true;
  }
  REP(i,M){
    graph[a[i]][b[i]]=false;
    graph[b[i]][a[i]]=false;
    vector<bool>seen(N);
    dfs(0,N,seen,graph);
    bool flag=false;
    REP(i,N){
      if(seen[i]==false)flag=true;
    }
    ans+=flag;
    graph[a[i]][b[i]]=true;
    graph[b[i]][a[i]]=true;
  }
  cout<<ans<<endl;
}

Submission Info

Judge Result