competitive-programming/codeforces/rounds/383-students-and-shoelaces.cpp at main · UnknownHacker1/competitive-programming · GitHub

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/*
 * Students and Shoelaces  [129B]
 * Problem:  https://codeforces.com/problemset/problem/129/B
 * Verdict:  ACCEPTED        Solved: 2021-01-18
 * Language: C++17 (GCC 7-32)
 * Runtime:  62 ms     Memory: 300 KB
 * Tags:     brute force, dfs and similar, graphs, implementation
 * Author:   BidoTeima
 * Source:   https://codeforces.com/contest/129/submission/104681813
 */

#include <bits/stdc++.h>
using namespace std;
// Important functions and defines
/// BidoTeima legacy functions
typedef long long ll;
ll POW(ll a, ll b) {
   ll res = 1;
   while(b > 0) {
    if(b%2==1) res*=a;
    a*=a;
    b/=2;
   }
   return res;
}
ll sum_range2d(ll i, ll j, ll k, ll l, vector<vector<ll>>& sum) {
    return sum[k][l] - sum[k][j - 1] - sum[i - 1][l] + sum[i - 1][j - 1];
}
ll gcd(ll a, ll b) {
    return (b == 0 ? abs(a) : gcd(b, a % b));
}
ll dist(ll X1, ll Y1, ll X2, ll Y2) {
    return sqrt( POW(X1-X2, 2) + POW(Y1-Y2,2) );
}
bool intersect(pair<int, int> p1, pair<int, int> p2) {
  int x1 = p1.first, x2 = p1.second, y1 = p2.first, y2 = p2.second;
  return (x1 >= y1 && x1 <= y2) ||
         (x2 >= y1 && x2 <= y2) ||
         (y1 >= x1 && y1 <= x2) ||
         (y2 >= x1 && y2 <= x2);
}
bool isPrime(ll n) {
    for(ll i = 2; i * i <= n; i++) if(n%i==0) return false;
    return true;
}
/*vector<bool> prime(10000005, true);
void sievePrime(ll n)
{
    for (int p=2; p*p<=n; p++)
    {
        if (prime[p] == true)
        {
            for (int i=p*p; i<=n; i += p)
                prime[i] = false;
        }
    }
}*/
bool isVowel(char ch) {
    return ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u';
}
/// End of BidoTeima legacy functions
#define SCD(t) scanf("%d",&t)
#define SCLD(t) scanf("%ld",&t)
#define SCLLD(t) scanf("%lld",&t)
#define SCC(t) scanf("%c",&t)
#define SCS(t) scanf("%s",t)
#define SCF(t) scanf("%f",&t)
#define SCLF(t) scanf("%lf",&t)
#define all(cont) cont.begin(), cont.end()
#define f first
#define s second
#define fast     ios::sync_with_stdio(0);cout.tie(0);cin.tie(0);
//End
vector<vector<int>> adj(1005);
int32_t main()
{
    ///freopen ("output.txt","w",stdout);
    ///freopen("input.txt", "r", stdin);
    fast
    int n, m;
    cin>>n>>m;
    for(int i = 0; i < m; i++) {
        int x, y;
        cin>>x>>y;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    int ans = 0;
    for(int x = 0; x < n; x++) {
        bool found = false;
        bool is[n+1];
        fill(is,is+n+1,false);
        for(int i = 1; i <= n; i++) {
            if(adj[i].size()==1) {
                found = true;
                is[i]=(is[i]==0 && is[adj[i][0]]==0);
            }
        }
        for(int i = 1; i <= n; i++) {
            if(is[i]) {
                adj[adj[i][0]].erase(find(adj[adj[i][0]].begin(),
                                    adj[adj[i][0]].end(), i));
                adj[i].pop_back();
            }
        }
        if(found) ++ans;
    }
    cout<<ans;
    return 0;
}