oj.uz

Submission #604949

# Submission time Handle Problem Language Result Execution time Memory
604949 2022-07-25T11:05:37 Z pakhomovee One-Way Streets (CEOI17_oneway) C++17
100 / 100
 228 ms 38016 KB 
#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <algorithm>
#include <iomanip>
#include <unordered_set>
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("O2")
using namespace std;

int timer = 0;
int timer1 = 0;

bool IS_BRIDGE[200000];

void dfs(int v, int p, vector<bool>& used, vector<vector<pair<int, int>>>& g, vector<int>& tin, vector<int>& up)
{
	tin[v] = timer++;
	up[v] = tin[v];
	used[v] = true;
	for (pair<int, int> x : g[v])
	{
		int u = x.first;
		int i = x.second;
		if (!used[u])
		{
			dfs(u, v, used, g, tin, up);
			up[v] = min(up[v], up[u]);
			if (up[u] > tin[v])
			{
				IS_BRIDGE[i] = true;
			}
		}
		else if (u != p)
		{
			up[v] = min(up[v], tin[u]);
		}
	}
}

void dfs1(int v, vector<int>& used, vector<vector<pair<int, int>>>& g, int cnt)
{
	used[v] = cnt;
	for (pair<int, int> x : g[v])
	{
		int u = x.first;
		int i = x.second;
		if (!IS_BRIDGE[i] && !used[u])
		{
			dfs1(u, used, g, cnt);
		}
	}
}

int par[17][100000];
int h[100000];

void dfs2(int v, int p, vector<bool>& used, vector<int>& tin, vector<int>& tout, vector<vector<int>>& g)
{
	used[v] = true;
	par[0][v] = p;
	if (p == v)
		h[v] = 0;
	else
		h[v] = h[p] + 1;
	for (int i = 1; i < 17; ++i)
	{
		par[i][v] = par[i - 1][par[i - 1][v]];
	}
	tin[v] = timer1++;
	for (int u : g[v])
	{
		if (!used[u])
		{
			dfs2(u, p, used, tin, tout, g);
		}
	}
	tout[v] = timer1++;
}

bool ok(int a, int b, vector<int>& tin, vector<int>& tout)
{
	if (tin[a] <= tin[b] && tout[a] >= tout[b]) return true;
	return false;
}

int get_lca(int a, int b, vector<int>& tin, vector<int>& tout)
{
	for (int i = 16; i >= 0; --i)
	{
		if (!ok(par[i][a], b, tin, tout))
		{
			a = par[i][a];
		}
	}
	a = par[0][a];
	return a;
}

void dfs3(int v, vector<bool>& used, vector<vector<int>>& g, vector<int>& lol, int w)
{
	h[v] = w;
	used[v] = true;
	for (int u : g[v])
	{
		if (!used[u])
		{
			dfs3(u, used, g, lol, w + 1);
			lol[v] += lol[u];
		}
	}
}

signed main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int n, m;
	cin >> n >> m;
	for (int i = 0; i < m; ++i)
	{
		IS_BRIDGE[i] = false;
	}
	vector<vector<pair<int, int>>> g(n);
	vector<int> ans(m, 0);
	map<pair<int, int>, int> d;
	vector<pair<int, int>> e;
	for (int i = 0; i < m; ++i)
	{
		int u, v;
		cin >> u >> v;
		--u; --v;
		e.push_back({ u, v });
		if (u > v) swap(u, v);
		if (d.count({ u, v }))
		{
			ans[d[{u, v}]] = -1;
		}
		d[{u, v}] = i;
		g[u].push_back({ v, i });
		g[v].push_back({ u, i });
	}
	vector<bool> used(n, false);
	vector<int> tin(n), up(n);
	for (int i = 0; i < n; ++i)
	{
		if (!used[i])
		{
			dfs(i, -1, used, g, tin, up);
		}
	}
	for (int i = 0; i < m; ++i)
	{
		if (IS_BRIDGE[i] && ans[i] == -1)
		{
			IS_BRIDGE[i] = false;
		}
		if (!IS_BRIDGE[i])
		{
			ans[i] = -1;
		}
		//cout << IS_BRIDGE[i] << ' ';
	}
	vector<vector<int>> g1(n);
	vector<int> used1(n, 0);
	int cnt = 1;
	for (int i = 0; i < n; ++i)
	{
		if (!used1[i])
		{
			dfs1(i, used1, g, cnt++);
		}
	}
	for (int i = 0; i < n; ++i)
	{
		--used1[i];
	}
	g1.resize(cnt - 1);
	for (int i = 0; i < n; ++i)
	{
		for (pair<int, int> x : g[i])
		{
			int u = x.first;
			int j = x.second;
			if (IS_BRIDGE[j])
			{
				g1[used1[i]].push_back(used1[u]);
				g1[used1[u]].push_back(used1[i]);
			}
		}
	}
	vector<bool> used2(cnt, false);
	vector<int> tout(cnt);
	vector<int> lol(cnt, 0);
	tin.resize(cnt);
	for (int i = 0; i < cnt - 1; ++i)
	{
		if (!used2[i])
		{
			dfs2(i, 0, used2, tin, tout, g1);
		}
	}
	int p;
	cin >> p;
	for (int i = 0; i < p; ++i)
	{
		int u, v;
		cin >> u >> v;
		--u; --v;
		u = used1[u];
		v = used1[v];
		lol[u] += -1;
		lol[v] += 1;
	}
	used2.assign(cnt, false);
	for (int i = 0; i < cnt - 1; ++i)
	{
		if (!used2[i])
		{
			dfs3(i, used2, g1, lol, 0);
		}
	}
	for (int i = 0; i < m; ++i)
	{
		int u = e[i].first;
		int v = e[i].second;
		u = used1[u];
		v = used1[v];
		//cout << i << ' ' << u << ' ' << v << ' ' << lol[u] << ' ' << lol[v] << endl;
		if ((h[u] > h[v] && lol[u] != 0) || (h[v] > h[u] && lol[v] != 0))
		{
			if (h[u] > h[v] && lol[u] < 0)
			{
				ans[i] = 1;
			}
			else if (h[u] > h[v] && lol[u] > 0)
			{
				ans[i] = 2;
			}
			else if (h[u] < h[v] && lol[v] < 0)
			{
				ans[i] = 2;
			}
			else if (h[u] < h[v] && lol[v] > 0)
			{
				ans[i] = 1;
			}
		}
		else
		{
			ans[i] = -1;
		}
	}
	for (int i : ans)
	{
		if (i == -1)
		{
			cout << 'B';
		}
		else if (i == 1)
		{
			cout << 'R';
		}
		else
		{
			cout << 'L';
		}
	}
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 592 KB Output is correct
4 Correct 1 ms 596 KB Output is correct
5 Correct 1 ms 716 KB Output is correct
6 Correct 1 ms 468 KB Output is correct
7 Correct 2 ms 724 KB Output is correct
8 Correct 1 ms 596 KB Output is correct
9 Correct 1 ms 464 KB Output is correct
10 Correct 1 ms 460 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 592 KB Output is correct
4 Correct 1 ms 596 KB Output is correct
5 Correct 1 ms 716 KB Output is correct
6 Correct 1 ms 468 KB Output is correct
7 Correct 2 ms 724 KB Output is correct
8 Correct 1 ms 596 KB Output is correct
9 Correct 1 ms 464 KB Output is correct
10 Correct 1 ms 460 KB Output is correct
11 Correct 102 ms 14468 KB Output is correct
12 Correct 115 ms 16128 KB Output is correct
13 Correct 139 ms 18436 KB Output is correct
14 Correct 143 ms 22848 KB Output is correct
15 Correct 165 ms 24648 KB Output is correct
16 Correct 224 ms 30892 KB Output is correct
17 Correct 187 ms 32744 KB Output is correct
18 Correct 211 ms 30816 KB Output is correct
19 Correct 200 ms 34336 KB Output is correct
20 Correct 104 ms 16464 KB Output is correct
21 Correct 101 ms 15864 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 592 KB Output is correct
4 Correct 1 ms 596 KB Output is correct
5 Correct 1 ms 716 KB Output is correct
6 Correct 1 ms 468 KB Output is correct
7 Correct 2 ms 724 KB Output is correct
8 Correct 1 ms 596 KB Output is correct
9 Correct 1 ms 464 KB Output is correct
10 Correct 1 ms 460 KB Output is correct
11 Correct 102 ms 14468 KB Output is correct
12 Correct 115 ms 16128 KB Output is correct
13 Correct 139 ms 18436 KB Output is correct
14 Correct 143 ms 22848 KB Output is correct
15 Correct 165 ms 24648 KB Output is correct
16 Correct 224 ms 30892 KB Output is correct
17 Correct 187 ms 32744 KB Output is correct
18 Correct 211 ms 30816 KB Output is correct
19 Correct 200 ms 34336 KB Output is correct
20 Correct 104 ms 16464 KB Output is correct
21 Correct 101 ms 15864 KB Output is correct
22 Correct 195 ms 33924 KB Output is correct
23 Correct 197 ms 31676 KB Output is correct
24 Correct 228 ms 31952 KB Output is correct
25 Correct 187 ms 38016 KB Output is correct
26 Correct 190 ms 33404 KB Output is correct
27 Correct 224 ms 31796 KB Output is correct
28 Correct 60 ms 5280 KB Output is correct
29 Correct 114 ms 17088 KB Output is correct
30 Correct 112 ms 17096 KB Output is correct
31 Correct 117 ms 17564 KB Output is correct
32 Correct 112 ms 22196 KB Output is correct