Submission #936029

#	Time	Username	Problem	Language	Result	Execution time	Memory
936029		Regulus	Naboj (COCI22_naboj)	C++17	0 / 110	177 ms	40128 KiB

naboj

#include <bits/stdc++.h>
#define IO ios::sync_with_stdio(false);cin.tie(0);
#define debug(x) cerr << #x << " = " << (x) << ' '
#define bug(x) cerr << (x) << ' '
#define endl cerr << '\n'
#define all(v) (v).begin(), (v).end()
#define SZ(v) (ll)(v).size()
#define lowbit(x) (x)&-(x)
#define pb emplace_back
#define F first
#define S second
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
//#define TEST
const int N = 2e5+5;
bool del[N];
set<pll> g[N];
vector<pll> ans;
priority_queue<pll, vector<pll>, greater<pll> > pq;

inline void no() { cout << "-1\n"; exit(0); }

int main(void)
{ IO
    int n, i, m;

    cin >> n >> m;
    if (m != n-1) assert(0);
    for (i=0; i < m; ++i)
    {
        int x, y; cin >> x >> y;
        g[x].insert({y, 1}), g[y].insert({y, 0});
    }

    for (i=1; i <= n; ++i) pq.push({SZ(g[i]), i});
    while (!pq.empty())
    {
        int deg = pq.top().F, x = pq.top().S; pq.pop();
        if (deg != 1)
        {
            if (!pq.empty()) no();
            ans.pb(x, 0);
            break;
        }

        pll p = *g[x].begin();
        int v = p.F, f = p.S;
        ans.pb(x, f);

        g[v].erase({x, f^1});
    }
    
    cout << SZ(ans) << '\n';
    for (auto p : ans) cout << p.F << ' ' << p.S << '\n';

    return 0;
}

• Subtask 1: 0 / 15
• Subtask 2: 0 / 25
• Subtask 3: 0 / 70