Submission #926172

#	Time	Username	Problem	Language	Result	Execution time	Memory
926172		GrindMachine	Newspapers (CEOI21_newspapers)	C++17	4 / 100	1 ms	604 KiB

newspapers

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "YES" << endl
#define no cout << "NO" << endl

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*



*/

const int MOD = 1e9 + 7;
const int N = 1e3 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

vector<ll> adj[N];
set<ll> st[N];
vector<ll> par(N);

void dfs1(ll u, ll p){
    par[u] = p;
    st[u].clear();
    bool leaf = true;

    trav(v,adj[u]){
        if(v == p) conts;
        dfs1(v,u);
        leaf = false;
    }

    if(p != -1){
        ll parp = par[p];
        if(parp != -1){
            st[parp].insert(p);
        }
    }
}

void solve(int test_case)
{
    ll n,m; cin >> n >> m;
    rep1(i,m){
        ll u,v; cin >> u >> v;
        adj[u].pb(v), adj[v].pb(u);
    }

    if(m != n-1){
        no;
        return;
    }

    if(n == 1){
        yes;
        cout << 1 << endl << 1 << endl;
        return;
    }

    rep1(i,n){
        dfs1(i,-1);
        bool ok = true;
        rep1(u,n){
            if(sz(st[u]) >= 2){
                ok = false;
            }
        }

        if(ok){
            yes;
            cout << 1 << endl << 1 << endl;
            return;
        }
    }

    no;

    // yes;
    // vector<ll> ans;
    // for(int i = 2; i <= n; ++i){
    //     ans.pb(i);
    // }
    // if(!((n-1)&1)){
    //     ans.pb(1);
    // }
    // for(int i = 2; i <= n; ++i){
    //     ans.pb(i);
    // }

    // cout << sz(ans) << endl;
    // trav(x,ans) cout << x << " ";
    // cout << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

Compilation message (stderr)

newspapers.cpp: In function 'void dfs1(ll, ll)':
newspapers.cpp:67:10: warning: variable 'leaf' set but not used [-Wunused-but-set-variable]
   67 |     bool leaf = true;
      |          ^~~~

• Subtask 1: 0 / 12
• Subtask 2: 4 / 8
• Subtask 3: 0 / 80