oj.uz

Submission #823658

# Submission time Handle Problem Language Result Execution time Memory
823658 2023-08-12T23:48:27 Z NK_ One-Way Streets (CEOI17_oneway) C++17
100 / 100
 57 ms 16996 KB 
// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>

using namespace std;

#define nl '\n'
#define pb push_back
#define mp make_pair
#define f first
#define s second
#define sz(x) int(x.size())

template<class T> using V = vector<T>;
using vi = V<int>;
using pi = pair<int, int>;

struct DSU {
	vi e; void init(int N) { e = vi(N, -1); }
	int get(int x) { return e[x] < 0 ? x : e[x] = get(e[x]); }
	bool unite(int x, int y) {
		x = get(x), y = get(y); if (x == y) return 0;
		e[x] += e[y]; e[y] = x; return 1;
	}
};
int main() {
	cin.tie(0)->sync_with_stdio(0);
	
	int N, M; cin >> N >> M;

	DSU D; D.init(N);
	V<V<pi>> adj(N); V<pi> ex, E;
	string ans(M, 'B');
	for(int i = 0; i < M; i++) {
		int u, v; cin >> u >> v; --u, --v;
		E.pb(mp(u, v));
		if (D.unite(u, v)) adj[u].pb(mp(v, i)), adj[v].pb(mp(u, i));
		else ex.pb(mp(u, v));
	}

	V<pi> par(N); vi dep(N, -1);
	function<void(int)> dfs = [&](int u) {
		for(auto& v : adj[u]) if (v.f != par[u].f) { 
			par[v.f] = mp(u, v.s); dep[v.f] = dep[u] + 1; dfs(v.f); 
		}
	};
	
	for(int r = 0; r < N; r++) if (dep[r] == -1) {
		par[r] = mp(-1, -1); dep[r] = 0; dfs(r);
	}


	D.init(N);
	for(auto& p : ex) {
		auto [u, v] = p;

		while(1) {
			int a = D.get(u), b = D.get(v);
			if (a == b) break;
			if (dep[a] < dep[b]) swap(a, b);
			assert(par[a].f != -1); D.unite(par[a].f, a);
		}
	}

	// assert(false);
	// V<V<pi>> ADJ(N);
	// for(int u = 0; u < N; u++) for(auto& v : adj[u]) if (D.get(v.f) != D.get(u)) {
	// 	int a = D.get(u), b = D.get(v.f);
	// 	ADJ[a].pb(mp(b, v.s));
	// }


	// adj.swap(ADJ);
	// par[0] = mp(-1, -1); dep[0] = 0; dfs(0);


	vi to(M, -1);
	int Q; cin >> Q;
	for(int i = 0; i < Q; i++) {
		int u, v; cin >> u >> v; --u, --v;
		if (D.get(u) == D.get(v)) continue;

		// cout << u << " " << v << endl;

		while(1) {
			int a = D.get(u), b = D.get(v);
			// cout << u << " " << v << endl;
			// cout << a << " " << b << endl;
			if (a == b) break;
			if (dep[a] < dep[b]) swap(a, b);
			// cout << D.get(u) << " -> " << a << endl;
			// change label of edge
			to[par[a].s] = (D.get(u) == a ? par[a].f : a);
			assert(par[a].f != -1); D.unite(par[a].f, a);
		}
	}

	for(int i = 0; i < M; i++) if (to[i] != -1) {
		// cout << to[i] << endl;
		ans[i] = (E[i].f == to[i] ? 'L' : 'R');
	}

	cout << ans << nl;

    return 0;
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 320 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 328 KB Output is correct
9 Correct 0 ms 340 KB Output is correct
10 Correct 1 ms 340 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 320 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 328 KB Output is correct
9 Correct 0 ms 340 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 20 ms 4848 KB Output is correct
12 Correct 24 ms 5692 KB Output is correct
13 Correct 30 ms 7032 KB Output is correct
14 Correct 33 ms 8872 KB Output is correct
15 Correct 34 ms 9524 KB Output is correct
16 Correct 39 ms 10432 KB Output is correct
17 Correct 34 ms 12332 KB Output is correct
18 Correct 39 ms 10424 KB Output is correct
19 Correct 41 ms 13636 KB Output is correct
20 Correct 27 ms 7040 KB Output is correct
21 Correct 30 ms 7308 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 320 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 328 KB Output is correct
9 Correct 0 ms 340 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 20 ms 4848 KB Output is correct
12 Correct 24 ms 5692 KB Output is correct
13 Correct 30 ms 7032 KB Output is correct
14 Correct 33 ms 8872 KB Output is correct
15 Correct 34 ms 9524 KB Output is correct
16 Correct 39 ms 10432 KB Output is correct
17 Correct 34 ms 12332 KB Output is correct
18 Correct 39 ms 10424 KB Output is correct
19 Correct 41 ms 13636 KB Output is correct
20 Correct 27 ms 7040 KB Output is correct
21 Correct 30 ms 7308 KB Output is correct
22 Correct 49 ms 13452 KB Output is correct
23 Correct 56 ms 11492 KB Output is correct
24 Correct 57 ms 11652 KB Output is correct
25 Correct 52 ms 16996 KB Output is correct
26 Correct 48 ms 12984 KB Output is correct
27 Correct 49 ms 11604 KB Output is correct
28 Correct 20 ms 3608 KB Output is correct
29 Correct 41 ms 8208 KB Output is correct
30 Correct 37 ms 8208 KB Output is correct
31 Correct 42 ms 8144 KB Output is correct
32 Correct 41 ms 12404 KB Output is correct