Submission #648043

#	Time	Username	Problem	Language	Result	Execution time	Memory
648043		gokussjz	Senior Postmen (BOI14_postmen)	C++17	0 / 100	1 ms	316 KiB

postmen

#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;

#define all(x)      x.begin(), x.end()
#define pb          push_back
#define sz(x)       (int)(x.size())
#define ll          long long
#define fi          first
#define se          second
#define lbd         lower_bound
#define ubd         upper_bound

template <typename T>
using ordered_set = tree<T, null_type,
      less<T>, rb_tree_tag,
      tree_order_statistics_node_update>;

const int MOD = 1e9 + 7;
const double eps = 1e-10;
const long long INF = 1e18;
const int N = 2e5 + 10;

struct Euler_Path {
	int n, src;
	bool circuit;
	vector<bool> vis;
	vector<set<int>> adj;
	vector<int> deg, path;
	void init(int _n, int x = 0, bool ok = 1) {
		n = _n;
		src = x;
		circuit = ok;
		adj.resize(n);
		vis.resize(n);
		deg.resize(n);
	}
	void add_edge(int u, int v) {
		adj[u].insert(v);
		adj[v].insert(u);
		deg[u]++, deg[v]++;
	}
	void dfs(int u) {
		vis[u] = 1;
		for (auto v : adj[u]) {
			if (!vis[v]) dfs(v);
		}
	}
	bool is_connected() {
		dfs(src);
		for (int i = 0; i < n; i++) {
			if (!adj[i].empty() && !vis[i]) return false;
		}
		return true;
	}
	void euler_dfs(int u) {
		while (!adj[u].empty()) {
			auto v = *adj[u].begin();
			adj[u].erase(adj[u].begin());
			adj[v].erase(u);
			euler_dfs(v);
		}
		path.pb(u);
	}
	vector<int> euler_path() {
		if (!is_connected()) return path;
		int cnt = 0;
		for (int i = 0; i < n; i++) {
			if (deg[i] & 1) {
				src = i;
				cnt++;
			}
		}
		if (circuit) {
			if (cnt) return path;
		} else {
			if ((cnt != 2) && cnt) return path;
		}
		euler_dfs(src);
		return path;
	}
} idk;

void solve() {
	int n, m;
	cin >> n >> m;
	idk.init(n, 0, 1);
	for (int i = 0; i < m; i++) {
		int u, v;
		cin >> u >> v;
		--u, --v;
		idk.add_edge(u, v);
	}
	vector<int> ans = idk.euler_path();
	assert(!ans.empty());
	vector<int> cycles;
	bool vis[n] = {};
	vector<vector<int>> fin;
	for (int it : ans) {
		if (vis[it]) {
			vector<int> curr;
			curr.pb(it);
			while (cycles.back() != it) {
				curr.pb(cycles.back());
				vis[cycles.back()] = 0;
				cycles.pop_back();
			}
			fin.pb(curr);
		} else {
			vis[it] = 1;
			cycles.pb(it);
		}
	}
	for (auto v : fin) {
		cout << sz(v) << ' ';
		for (auto it : v) cout << it + 1 << ' ';
		cout << '\n';
	}
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	int tt = 1;
	//cin >> tt;
	while (tt--) {
		solve();
		cout << '\n';
	}
	return 0;
}

• Subtask 1: 0 / 38
• Subtask 2: 0 / 17
• Subtask 3: 0 / 45