oj.uz

Submission #823665

# Submission time Handle Problem Language Result Execution time Memory
823665 2023-08-12T23:50:18 Z NK_ One-Way Streets (CEOI17_oneway) C++17
100 / 100
 69 ms 14776 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);
			assert(par[a].f != -1); 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);
			assert(par[a].f != -1); 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 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 364 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 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 364 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 24 ms 3772 KB Output is correct
12 Correct 22 ms 4548 KB Output is correct
13 Correct 26 ms 5868 KB Output is correct
14 Correct 33 ms 7648 KB Output is correct
15 Correct 33 ms 8288 KB Output is correct
16 Correct 37 ms 9240 KB Output is correct
17 Correct 34 ms 11132 KB Output is correct
18 Correct 35 ms 9272 KB Output is correct
19 Correct 32 ms 12484 KB Output is correct
20 Correct 36 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 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 364 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 24 ms 3772 KB Output is correct
12 Correct 22 ms 4548 KB Output is correct
13 Correct 26 ms 5868 KB Output is correct
14 Correct 33 ms 7648 KB Output is correct
15 Correct 33 ms 8288 KB Output is correct
16 Correct 37 ms 9240 KB Output is correct
17 Correct 34 ms 11132 KB Output is correct
18 Correct 35 ms 9272 KB Output is correct
19 Correct 32 ms 12484 KB Output is correct
20 Correct 36 ms 5892 KB Output is correct
21 Correct 24 ms 6148 KB Output is correct
22 Correct 47 ms 11116 KB Output is correct
23 Correct 48 ms 9280 KB Output is correct
24 Correct 69 ms 9340 KB Output is correct
25 Correct 47 ms 14776 KB Output is correct
26 Correct 47 ms 10680 KB Output is correct
27 Correct 52 ms 9388 KB Output is correct
28 Correct 19 ms 2388 KB Output is correct
29 Correct 37 ms 5816 KB Output is correct
30 Correct 45 ms 5868 KB Output is correct
31 Correct 38 ms 5884 KB Output is correct
32 Correct 39 ms 10220 KB Output is correct