oj.uz

Submission #823659

# Submission time Handle Problem Language Result Execution time Memory
823659 2023-08-12T23:49:31 Z NK_ One-Way Streets (CEOI17_oneway) C++17
100 / 100
 54 ms 14716 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(const 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 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 0 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 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 0 ms 340 KB Output is correct
11 Correct 18 ms 3816 KB Output is correct
12 Correct 26 ms 4636 KB Output is correct
13 Correct 27 ms 5892 KB Output is correct
14 Correct 32 ms 7656 KB Output is correct
15 Correct 33 ms 8388 KB Output is correct
16 Correct 36 ms 9272 KB Output is correct
17 Correct 32 ms 11120 KB Output is correct
18 Correct 41 ms 9264 KB Output is correct
19 Correct 35 ms 12544 KB Output is correct
20 Correct 26 ms 5840 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 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 0 ms 340 KB Output is correct
11 Correct 18 ms 3816 KB Output is correct
12 Correct 26 ms 4636 KB Output is correct
13 Correct 27 ms 5892 KB Output is correct
14 Correct 32 ms 7656 KB Output is correct
15 Correct 33 ms 8388 KB Output is correct
16 Correct 36 ms 9272 KB Output is correct
17 Correct 32 ms 11120 KB Output is correct
18 Correct 41 ms 9264 KB Output is correct
19 Correct 35 ms 12544 KB Output is correct
20 Correct 26 ms 5840 KB Output is correct
21 Correct 24 ms 6148 KB Output is correct
22 Correct 54 ms 11128 KB Output is correct
23 Correct 48 ms 9212 KB Output is correct
24 Correct 52 ms 9272 KB Output is correct
25 Correct 48 ms 14716 KB Output is correct
26 Correct 47 ms 10680 KB Output is correct
27 Correct 49 ms 9380 KB Output is correct
28 Correct 19 ms 2456 KB Output is correct
29 Correct 37 ms 5824 KB Output is correct
30 Correct 38 ms 5876 KB Output is correct
31 Correct 38 ms 5892 KB Output is correct
32 Correct 40 ms 10184 KB Output is correct