Submission #877795

#	Time	Username	Problem	Language	Result	Execution time	Memory
877795		Alora	Naboj (COCI22_naboj)	C++17	110 / 110	263 ms	30292 KiB

naboj

#include <bits/stdc++.h>
#define Alora "cownav"
#define fi(i,a,b) for(int i = a; i <= b; i++)
#define fid(i,a,b) for(int i = a; i >= b; i--)
#define ll long long
#define f first
#define se second
#define pii pair<int, int>
#define getbit(i, j) ((i >> j) & 1)
#define all(v) v.begin(), v.end()
#define pb push_back
#define maxn 300005
const int M = 1e9 + 7;
using namespace std;
int n, m, sl, cnt[maxn][4];
pii ans[maxn];
queue <int> q;
vector <int> g[maxn];
 
int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(NULL);
	if(fopen(Alora".inp", "r")){
    freopen(Alora".inp", "r", stdin);
    freopen(Alora".out", "w", stdout);}
    cin >> n >> m;
    fi(i, 1, m){
        int u, v; cin >> u >> v;
        g[u].pb(v); cnt[u][1]++;
        g[v].pb(u); cnt[v][0]++;
    }
    fi(u, 1, n) if(cnt[u][1] == 0 || cnt[u][0] == 0) q.push(u);
    while(q.size()){
        int u = q.front(); q.pop();
        if(cnt[u][1] + cnt[u][0] == 0) continue;
        int t = (cnt[u][0] > 0 ? 0 : 1);
        cnt[u][t] = 0;
        //cout << u << " " << t << endl;
        ans[++sl] = {u, t};
        for(auto v: g[u]) if(cnt[v][1 - t]){
            cnt[v][1 - t]--;
            if(cnt[v][1 - t] == 0) q.push(v);
        }
    }
    fi(i, 1, n) if(cnt[i][0] + cnt[i][1]) {cout << -1; return 0;}
    cout << sl << '\n';
    fid(i, sl, 1) cout << ans[i].f << " " << ans[i].se << '\n';
    return 0;
}

Compilation message (stderr)

naboj.cpp: In function 'int main()':
naboj.cpp:24:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   24 |     freopen(Alora".inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
naboj.cpp:25:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   25 |     freopen(Alora".out", "w", stdout);}
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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