oj.uz

답안 #570443

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
570443 2022-05-29T23:56:21 Z aryan12 Usmjeri (COCI17_usmjeri) C++17
140 / 140
 788 ms 105456 KB 
#include <bits/stdc++.h>
using namespace std;
#define int long long

mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());

const int N = 3e5 + 5, M = 3e5 + 5, MOD = 1e9 + 7;
int depth[N], min_depth[N];
vector<int> g[N];
vector<array<int, 2> > g2[N];
int dp[19][N];
int color[N];
bool vis[N];

void dfs(int node, int par)
{
	dp[0][node] = par;
	for(int to: g[node])
	{
		if(to == par) continue;
		depth[to] = depth[node] + 1;
		min_depth[to] = depth[to];
		dfs(to, node);
	}
}

int LCA(int x, int y)
{
	if(depth[x] > depth[y]) swap(x, y);
	int diff = depth[y] - depth[x];
	for(int i = 18; i >= 0; i--)
	{
		if(diff & (1 << i))
		{
			y = dp[i][y];
		}
	}
	if(x == y) return x;
	for(int i = 18; i >= 0; i--)
	{
		if(dp[i][x] != dp[i][y])
		{
			x = dp[i][x];
			y = dp[i][y];
		}
	}
	return dp[0][x];
}

void again_dfs(int node, int par)
{
	for(int to: g[node])
	{
		if(to == par) continue;
		// cout << "to = " << to << ", node = " << node << "\n";
		again_dfs(to, node);
		min_depth[node] = min(min_depth[node], min_depth[to]);
		if(min_depth[to] < depth[node])
		{
			// cout << to << " <-> " << node << " with 0\n";
			g2[to].push_back({node, 0});
			g2[node].push_back({to, 0});
		}
	}
}

bool dfs_check(int node, int cur_color)
{
	vis[node] = true;
	if(color[node] == 0 || color[node] == cur_color)
	{
		color[node] = cur_color;
	}
	if(color[node] != cur_color) return false;
	for(auto [to, wt]: g2[node])
	{
		int next_color = (wt == 0) ? cur_color : 3 - cur_color;
		if(color[to] != 0 && color[to] != next_color) return false;
		if(vis[to]) continue;
		if(!dfs_check(to, next_color)) return false;
	}
	return true;
}

void Solve() 
{
	int n, m;
	cin >> n >> m;
	for(int i = 1; i < n; i++)
	{
		int u, v;
		cin >> u >> v;
		g[u].push_back(v);
		g[v].push_back(u);
	}
	depth[1] = 0;
	min_depth[1] = 0;
	dfs(1, -1);
	for(int i = 1; i < 19; i++)
	{
		for(int j = 1; j <= n; j++)
		{
			if(dp[i - 1][j] == -1)
			{
				dp[i][j] = -1;
			}
			else
			{
				dp[i][j] = dp[i - 1][dp[i - 1][j]];
			}
		}
	}
	for(int i = 1; i <= m; i++)
	{
		int u, v;
		cin >> u >> v;
		int lca = LCA(u, v);
		min_depth[u] = min(min_depth[u], depth[lca]);
		min_depth[v] = min(min_depth[v], depth[lca]);
		if(lca != u && lca != v)
		{
			g2[u].push_back({v, 1});
			g2[v].push_back({u, 1});
			// cout << u << " <-> " << v << " with 1\n";
		}
	}
	again_dfs(1, -1);
	int ans = 1;
	for(int i = 2; i <= n; i++)
	{
		if(!vis[i])
		{
			ans = (ans * 2) % MOD;
		}
		if(!vis[i] && !dfs_check(i, 1))
		{
			cout << "0\n";
			return;
		}
	}
	cout << ans << "\n";
}

int32_t main() 
{
	auto begin = std::chrono::high_resolution_clock::now();
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int t = 1;
	// cin >> t;
	for(int i = 1; i <= t; i++) 
	{
		//cout << "Case #" << i << ": ";
		Solve();
	}
	auto end = std::chrono::high_resolution_clock::now();
    auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
    cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n"; 
	return 0;
}

Subtask #1
14.0 / 14.0

# 결과 실행 시간 메모리 Grader output
1 Correct 93 ms 45868 KB Output is correct

Subtask #2
14.0 / 14.0

# 결과 실행 시간 메모리 Grader output
1 Correct 198 ms 105456 KB Output is correct

Subtask #3
14.0 / 14.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 14804 KB Output is correct
2 Correct 12 ms 15084 KB Output is correct

Subtask #4
14.0 / 14.0

# 결과 실행 시간 메모리 Grader output
1 Correct 9 ms 14804 KB Output is correct
2 Correct 10 ms 15088 KB Output is correct

Subtask #5
14.0 / 14.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 15700 KB Output is correct
2 Correct 10 ms 15724 KB Output is correct

Subtask #6
14.0 / 14.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 15700 KB Output is correct
2 Correct 11 ms 15700 KB Output is correct

Subtask #7
14.0 / 14.0

# 결과 실행 시간 메모리 Grader output
1 Correct 343 ms 82976 KB Output is correct
2 Correct 342 ms 93680 KB Output is correct
3 Correct 283 ms 66384 KB Output is correct

Subtask #8
14.0 / 14.0

# 결과 실행 시간 메모리 Grader output
1 Correct 788 ms 91456 KB Output is correct
2 Correct 710 ms 91188 KB Output is correct
3 Correct 371 ms 67404 KB Output is correct

Subtask #9
14.0 / 14.0

# 결과 실행 시간 메모리 Grader output
1 Correct 604 ms 92224 KB Output is correct
2 Correct 313 ms 83852 KB Output is correct
3 Correct 492 ms 73120 KB Output is correct

Subtask #10
14.0 / 14.0

# 결과 실행 시간 메모리 Grader output
1 Correct 577 ms 92588 KB Output is correct
2 Correct 505 ms 101300 KB Output is correct
3 Correct 263 ms 66240 KB Output is correct