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Submission #79334

# Submission time Handle Problem Language Result Execution time Memory
79334 2018-10-12T09:36:15 Z aminra One-Way Streets (CEOI17_oneway) C++14
100 / 100
 337 ms 32812 KB 
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
const int MOD = (int)1e9 + 7;
const int MAXN = (int)1e5 + 7;
const int infint = (int)1e9;
int visited[MAXN], is[MAXN], dp[MAXN], h[MAXN], n, m, par[MAXN], p[MAXN][20], up[MAXN], down[MAXN];
set< pair<int, int> > D;
pair<int, int> edge[MAXN];
vector<pair<int, int> > adj[MAXN];
vector<int> T[MAXN];
void dfs(int v, int index)
{
	dp[v] = h[v];
	visited[v] = 1;
	for(auto u : adj[v])
	{
		if(!visited[u.first])
		{
			h[u.first] = h[v] + 1;
			dfs(u.first, u.second);
			dp[v] = min(dp[v], dp[u.first]);
		}
		else
		{
			if(index != u.second)
				dp[v] = min(dp[v], h[u.first]);
		}
	}
	if(index != -1)
	{
		if(dp[v] == h[v])
			is[index] = 1;
	}
	return;
}
int get(int u)
{
	return par[u] < 0 ? u : par[u] = get(par[u]);
}
void merge(int u, int v)
{
	if((u = get(u)) == (v = get(v)))
		return;
	if(par[u] > par[v])
		swap(u, v); //par[u] > par[v]
	par[u] += par[v];
	par[v] = u;
}
void add(int u, int v)
{
	T[u].push_back(v);
	T[v].push_back(u);
}
void dfs_pre(int u, int P)
{
	visited[u] = 1, p[u][0] = P;
	for (auto v : T[u])
		if(v != P)
		{
			h[v] = h[u] + 1;
			dfs_pre(v, u);
		}
}
int lca(int u, int v)
{
	if(h[u] > h[v])
		swap(u, v);
	for (int i = 19; i >= 0; i--)
		if(h[v] - (1ll << i) >= h[u])	
			v = p[v][i];
	if(u == v)
		return u;
	for (int i = 19; i >= 0; i--)
		if(p[v][i] != p[u][i] && p[u][i] != -1 && p[v][i] != -1)
			v = p[v][i], u = p[u][i];
	return p[v][0];
}
void dfs_col(int u, int P)
{
	for (auto v : T[u])
		if(v != P)
		{
			dfs_col(v, u);
			down[u] += down[v];
			up[u] += up[v];
		}
	if(down[u])
		D.insert({P, u});
	if(up[u])
		D.insert({u, P});
}
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	cin >> n >> m;
	for (int i = 0; i < m; i++)
	{
		cin >> edge[i].first >> edge[i].second;
		adj[edge[i].first].push_back({edge[i].second, i});
		adj[edge[i].second].push_back({edge[i].first, i});
	}
	
	for (int i = 1; i <= n; i++)
		if(!visited[i])
			dfs(i, -1);
	memset(par, -1, sizeof par);
	for (int i = 0; i < m; i++)
		if(!is[i])
			merge(edge[i].first, edge[i].second);
	for (int i = 0; i < m; i++)
		if(get(edge[i].first) != get(edge[i].second))
		{
			int u = get(edge[i].first), v = get(edge[i].second);
			add(u, v);
		}
	memset(visited, 0, sizeof visited);
	memset(h, 0, sizeof h);
	memset(p, -1, sizeof p);
	for (int i = 1; i <= n; i++)
		if(!visited[i])
		{
			add(0, i);
			h[i] = 1;
			dfs_pre(i, 0);
		}
	for (int i = 1; i < 20; i++)
		for (int j = 1; j <= n; j++)
			if(p[j][i - 1] != -1)
				p[j][i] = p[p[j][i - 1]][i - 1];
	//derakht moalefeyae yal hambandesho gereftim.
	int q;
	cin >> q;
	for (int i = 0; i < q; i++)
	{
		int x, y;
		cin >> x >> y;
		x = get(x), y = get(y);
		int c = lca(x, y);
		up[x]++, up[c]--;
		down[y]++, down[c]--;
	}
	dfs_col(0, -1);
	for (int i = 0; i < m; i++)
	{
		int u = get(edge[i].first), v = get(edge[i].second);
		if(u == v)
			cout << 'B';
		else
		if(D.count({u, v}))
			cout << 'R';
		else
		if(D.count({v, u}))
			cout << 'L';
		else
			cout << 'B';
	}
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 14072 KB Output is correct
2 Correct 14 ms 14072 KB Output is correct
3 Correct 18 ms 14400 KB Output is correct
4 Correct 14 ms 14448 KB Output is correct
5 Correct 14 ms 14448 KB Output is correct
6 Correct 14 ms 14448 KB Output is correct
7 Correct 14 ms 14448 KB Output is correct
8 Correct 14 ms 14448 KB Output is correct
9 Correct 13 ms 14448 KB Output is correct
10 Correct 14 ms 14448 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 14072 KB Output is correct
2 Correct 14 ms 14072 KB Output is correct
3 Correct 18 ms 14400 KB Output is correct
4 Correct 14 ms 14448 KB Output is correct
5 Correct 14 ms 14448 KB Output is correct
6 Correct 14 ms 14448 KB Output is correct
7 Correct 14 ms 14448 KB Output is correct
8 Correct 14 ms 14448 KB Output is correct
9 Correct 13 ms 14448 KB Output is correct
10 Correct 14 ms 14448 KB Output is correct
11 Correct 69 ms 19036 KB Output is correct
12 Correct 77 ms 20460 KB Output is correct
13 Correct 91 ms 22176 KB Output is correct
14 Correct 110 ms 23948 KB Output is correct
15 Correct 151 ms 24332 KB Output is correct
16 Correct 163 ms 24332 KB Output is correct
17 Correct 223 ms 27148 KB Output is correct
18 Correct 144 ms 27148 KB Output is correct
19 Correct 194 ms 28488 KB Output is correct
20 Correct 76 ms 28488 KB Output is correct
21 Correct 82 ms 28488 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 14072 KB Output is correct
2 Correct 14 ms 14072 KB Output is correct
3 Correct 18 ms 14400 KB Output is correct
4 Correct 14 ms 14448 KB Output is correct
5 Correct 14 ms 14448 KB Output is correct
6 Correct 14 ms 14448 KB Output is correct
7 Correct 14 ms 14448 KB Output is correct
8 Correct 14 ms 14448 KB Output is correct
9 Correct 13 ms 14448 KB Output is correct
10 Correct 14 ms 14448 KB Output is correct
11 Correct 69 ms 19036 KB Output is correct
12 Correct 77 ms 20460 KB Output is correct
13 Correct 91 ms 22176 KB Output is correct
14 Correct 110 ms 23948 KB Output is correct
15 Correct 151 ms 24332 KB Output is correct
16 Correct 163 ms 24332 KB Output is correct
17 Correct 223 ms 27148 KB Output is correct
18 Correct 144 ms 27148 KB Output is correct
19 Correct 194 ms 28488 KB Output is correct
20 Correct 76 ms 28488 KB Output is correct
21 Correct 82 ms 28488 KB Output is correct
22 Correct 335 ms 29700 KB Output is correct
23 Correct 313 ms 29700 KB Output is correct
24 Correct 289 ms 29700 KB Output is correct
25 Correct 321 ms 32812 KB Output is correct
26 Correct 337 ms 32812 KB Output is correct
27 Correct 322 ms 32812 KB Output is correct
28 Correct 58 ms 32812 KB Output is correct
29 Correct 102 ms 32812 KB Output is correct
30 Correct 113 ms 32812 KB Output is correct
31 Correct 109 ms 32812 KB Output is correct
32 Correct 184 ms 32812 KB Output is correct