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답안 #118370

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
118370 2019-06-18T19:58:46 Z teomrn One-Way Streets (CEOI17_oneway) C++14
100 / 100
 283 ms 28792 KB 
#include <bits/stdc++.h>
using namespace std;

const int NMAX = 100010;
const int LGMAX = 20;

namespace UF {
	int tata[NMAX], g[NMAX];
	
	int find(int x) {
		if (tata[tata[x]] != tata[x])
			tata[x] = find(tata[x]);
		return tata[x];
	}

	bool unite(int a, int b) {
		a = find(a);
		b = find(b);
		if (a == b)
			return 0;
		if (g[a] < g[b])
			swap(a, b);
		tata[b] = a, g[a] += g[b];
		return 1;
	}

	void UF(int n) {
		fill(g, g + n + 1, 1);
		iota(tata, tata + n + 1, 0);
	}
}

bool in_cicle[NMAX];
char ans[NMAX];
vector <pair <int, int>> adia[NMAX];
int muchie_tata[NMAX];
int stramos[LGMAX][NMAX];
int h[NMAX];
int lazy[LGMAX][NMAX];
// for push: 0->nimic, 1->vreau in sus, 2->vreau in jos, 4->sunt in ciclu

void dfs(int nod, int tata)
{
	stramos[0][nod] = tata;
	h[nod] = 1 + h[tata];
	for (int i = 1; i < LGMAX; i++)
		stramos[i][nod] = stramos[i - 1][stramos[i - 1][nod]];
	
	for (auto i : adia[nod]) {
		if (i.first == tata)
			muchie_tata[nod] = i.second;
		else
			dfs(i.first, nod);
	}
}

int lca(int a, int b)
{
	if (h[a] < h[b])
		swap(a, b);
	for (int i = LGMAX - 1; i >= 0; i--)
		if (h[a] - (1 << i) >= h[b])
			a = stramos[i][a];
	
	if (a == b)
		return a;

	for (int i = LGMAX - 1; i >= 0; i--)
		if (stramos[i][a] != stramos[i][b])
			a = stramos[i][a], b = stramos[i][b];

	return stramos[0][a];
}

void push_on_chain(int from, int to, int val)
{
	/// to este NEAPARAT stramos de-al lui from
	int l = h[from] - h[to];
	for (int i = LGMAX - 1; i >= 0; i--) {
		if (l >= (1 << i)) {
			lazy[i][from] |= val;
			from = stramos[i][from];
			l -= (1 << i);
		}
	}
}

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

	int n, m, a, b;
	cin >> n >> m;

	UF::UF(n);

	vector <pair <int, int>> useless;

	for (int i = 1; i <= m; i++) {
		cin >> a >> b;
		if (!UF::unite(a, b)) {
			/// am un ciclu
			useless.push_back({ a, b });
			in_cicle[i] = 1;
			ans[i] = 'B';
		}
		else {
			adia[a].push_back({ b, i });
			adia[b].push_back({ a, -i });
		}
	}

	for (int i = 1; i <= n; i++)
		if (UF::find(i) == i)
			dfs(i, 0);

	for (auto i : useless) {
		int l = lca(i.first, i.second);
		push_on_chain(i.first, l, 4);
		push_on_chain(i.second, l, 4);
	}

	int q;
	cin >> q;

	while (q--) {
		cin >> a >> b;
		/// vreau sa ma duc de la a la b
		int l = lca(a, b);
		push_on_chain(a, l, 1);
		push_on_chain(b, l, 2);
	}

	for (int i = LGMAX - 1; i; i--) {
		for (int j = 1; j <= n; j++) {
			lazy[i - 1][j] |= lazy[i][j];
			lazy[i - 1][stramos[i - 1][j]] |= lazy[i][j];
		}
	}

	for (int i = 1; i <= n; i++) {
		if (muchie_tata[i] == 0)
			continue;
		bool sus = (lazy[0][i] & 1);
		bool jos = (lazy[0][i] & 2);
		int id = muchie_tata[i];
		int rev = (id < 0);
		id = abs(id);

		in_cicle[id] = (lazy[0][i] & 4);
		
		if (in_cicle[id])
			ans[id] = 'B';
		else {
			assert(!sus || !jos);
			if (sus)
				ans[id] = "RL"[rev];
			else if (jos)
				ans[id] = "LR"[rev];
			else
				ans[id] = 'B';
		}
	}

	for (int i = 1; i <= m; i++)
		cout << ans[i];

	cout << '\n';

	return 0;
}/*
5 6 
1 2 
1 2 
4 3 
2 3 
1 3 
5 1
2 
4 5 
1 3*/

Subtask #1
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 2944 KB Output is correct
2 Correct 4 ms 2944 KB Output is correct
3 Correct 5 ms 3072 KB Output is correct
4 Correct 5 ms 3072 KB Output is correct
5 Correct 6 ms 3200 KB Output is correct
6 Correct 5 ms 3044 KB Output is correct
7 Correct 5 ms 3200 KB Output is correct
8 Correct 5 ms 3200 KB Output is correct
9 Correct 5 ms 3072 KB Output is correct
10 Correct 4 ms 3072 KB Output is correct

Subtask #2
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 2944 KB Output is correct
2 Correct 4 ms 2944 KB Output is correct
3 Correct 5 ms 3072 KB Output is correct
4 Correct 5 ms 3072 KB Output is correct
5 Correct 6 ms 3200 KB Output is correct
6 Correct 5 ms 3044 KB Output is correct
7 Correct 5 ms 3200 KB Output is correct
8 Correct 5 ms 3200 KB Output is correct
9 Correct 5 ms 3072 KB Output is correct
10 Correct 4 ms 3072 KB Output is correct
11 Correct 70 ms 8664 KB Output is correct
12 Correct 77 ms 11076 KB Output is correct
13 Correct 89 ms 14956 KB Output is correct
14 Correct 122 ms 20724 KB Output is correct
15 Correct 118 ms 22588 KB Output is correct
16 Correct 129 ms 24724 KB Output is correct
17 Correct 110 ms 25484 KB Output is correct
18 Correct 111 ms 24696 KB Output is correct
19 Correct 103 ms 26364 KB Output is correct
20 Correct 75 ms 14956 KB Output is correct
21 Correct 67 ms 15088 KB Output is correct

Subtask #3
40.0 / 40.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 2944 KB Output is correct
2 Correct 4 ms 2944 KB Output is correct
3 Correct 5 ms 3072 KB Output is correct
4 Correct 5 ms 3072 KB Output is correct
5 Correct 6 ms 3200 KB Output is correct
6 Correct 5 ms 3044 KB Output is correct
7 Correct 5 ms 3200 KB Output is correct
8 Correct 5 ms 3200 KB Output is correct
9 Correct 5 ms 3072 KB Output is correct
10 Correct 4 ms 3072 KB Output is correct
11 Correct 70 ms 8664 KB Output is correct
12 Correct 77 ms 11076 KB Output is correct
13 Correct 89 ms 14956 KB Output is correct
14 Correct 122 ms 20724 KB Output is correct
15 Correct 118 ms 22588 KB Output is correct
16 Correct 129 ms 24724 KB Output is correct
17 Correct 110 ms 25484 KB Output is correct
18 Correct 111 ms 24696 KB Output is correct
19 Correct 103 ms 26364 KB Output is correct
20 Correct 75 ms 14956 KB Output is correct
21 Correct 67 ms 15088 KB Output is correct
22 Correct 283 ms 26652 KB Output is correct
23 Correct 235 ms 25848 KB Output is correct
24 Correct 207 ms 25948 KB Output is correct
25 Correct 281 ms 28792 KB Output is correct
26 Correct 252 ms 26644 KB Output is correct
27 Correct 211 ms 25804 KB Output is correct
28 Correct 65 ms 5228 KB Output is correct
29 Correct 146 ms 16112 KB Output is correct
30 Correct 151 ms 16236 KB Output is correct
31 Correct 133 ms 16112 KB Output is correct
32 Correct 226 ms 20832 KB Output is correct