oj.uz

Submission #823666

# Submission time Handle Problem Language Result Execution time Memory
823666 2023-08-12T23:50:32 Z NK_ One-Way Streets (CEOI17_oneway) C++17
100 / 100
 66 ms 14712 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) {
		int u, v; tie(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);
			D.unite(par[a].f, a);
		}
	}

	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;

		while(1) {
			int a = D.get(u), b = D.get(v);
			if (a == b) break;
			if (dep[a] < dep[b]) swap(a, b);
			to[par[a].s] = (D.get(u) == a ? par[a].f : a);
			D.unite(par[a].f, a);
		}
	}

	for(int i = 0; i < M; i++) if (to[i] != -1) {
		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 340 KB Output is correct
4 Correct 0 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Correct 1 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 340 KB Output is correct
4 Correct 0 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 19 ms 3780 KB Output is correct
12 Correct 22 ms 4560 KB Output is correct
13 Correct 33 ms 5864 KB Output is correct
14 Correct 35 ms 7640 KB Output is correct
15 Correct 34 ms 8308 KB Output is correct
16 Correct 38 ms 9336 KB Output is correct
17 Correct 32 ms 11172 KB Output is correct
18 Correct 38 ms 9272 KB Output is correct
19 Correct 43 ms 12472 KB Output is correct
20 Correct 27 ms 5892 KB Output is correct
21 Correct 24 ms 6148 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 340 KB Output is correct
4 Correct 0 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 19 ms 3780 KB Output is correct
12 Correct 22 ms 4560 KB Output is correct
13 Correct 33 ms 5864 KB Output is correct
14 Correct 35 ms 7640 KB Output is correct
15 Correct 34 ms 8308 KB Output is correct
16 Correct 38 ms 9336 KB Output is correct
17 Correct 32 ms 11172 KB Output is correct
18 Correct 38 ms 9272 KB Output is correct
19 Correct 43 ms 12472 KB Output is correct
20 Correct 27 ms 5892 KB Output is correct
21 Correct 24 ms 6148 KB Output is correct
22 Correct 51 ms 11100 KB Output is correct
23 Correct 66 ms 9376 KB Output is correct
24 Correct 66 ms 9260 KB Output is correct
25 Correct 51 ms 14712 KB Output is correct
26 Correct 54 ms 10724 KB Output is correct
27 Correct 47 ms 9400 KB Output is correct
28 Correct 19 ms 2504 KB Output is correct
29 Correct 40 ms 5820 KB Output is correct
30 Correct 38 ms 5856 KB Output is correct
31 Correct 46 ms 5884 KB Output is correct
32 Correct 51 ms 10308 KB Output is correct