oj.uz

Submission #668112

# Submission time Handle Problem Language Result Execution time Memory
668112 2022-12-02T19:19:28 Z dozer Star Trek (CEOI20_startrek) C++14
38 / 100
 71 ms 17764 KB 
#include <bits/stdc++.h>
using namespace std;
#define fastio() cin.tie(0), ios_base::sync_with_stdio(0)
#define fileio() freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout)
#define pb push_back
#define pii pair<int, int>
#define st first
#define nd second
#define sp " "
#define endl "\n"
#define modulo 1000000007
#define N 100005
#define int long long

int ans[N], dp[N], cnt[N], c[N];
vector<int> adj[N];

void dfs(int node, int root)
{
	dp[node] = 0;
	for (auto i : adj[node])
	{
		if (i == root) continue;
		dfs(i, node);
		if (dp[i] == 0) cnt[node]++, dp[node] = 1;
	}
	ans[node] = dp[node];
}

void reroot(int node, int root)
{
	for (auto i : adj[node])
	{
		if (i == root) continue;
		int curr = ans[node];
		if (cnt[node]== 1 && ans[i] == 0) curr = 0;
		if (curr == 0) cnt[i]++;
		if (cnt[i]) ans[i] = 1;
		reroot(i, node); 
	}
}

void critical(int node, int root)
{
	if (dp[node] == 0) c[node] = 1;
	if (dp[node] == 0)
	{
		for (auto i : adj[node])
		{
			if (i == root) continue;
			critical(i, node);
			if (dp[i] == 1) c[node] += c[i];
		}
	}
	else
	{
		int cntr = 0;
		for (auto i : adj[node])
		{
			if (i == root) continue;
			critical(i, node);
			if (dp[i] == 0) cntr++;
		}
		if (cntr == 1)
		{
			for (auto i : adj[node])
			{
				if (i == root) continue;
				if (dp[i] == 0) c[node] += c[i];
			}
		}
	}
}


int mul(int a, int b)
{
	return (a * b) % modulo;
}

int subs(int a, int b)
{
	if (a < b) return a - b + modulo;
	return a - b;
}

int32_t main()
{
	fastio();
	#ifndef ONLINE_JUDGE
	//fileio();
	#endif


	int n, d;
	cin>>n>>d;
	for (int i = 1; i < n; i++)
	{
		int u, v;
		cin>>u>>v;
		adj[u].pb(v);
		adj[v].pb(u);
	}

	dfs(1, 0);
	
	reroot(1, 0);
	critical(1, 0);
	
	int sum = 0;
	for (int i = 1; i <= n; i++) if (ans[i] == 0) sum++;
	int res;
	if (ans[1] == 0)
	{
		res = mul(sum, c[1]);
	}
	else
	{
		res = mul(n, n);
		res = subs(res, mul(sum, c[1]));
	}

	cout<<res<<endl;
	cerr<<"time taken : "<<(float)clock() / CLOCKS_PER_SEC<<" seconds\n";
}

Subtask #1
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Incorrect 2 ms 2644 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 7.0

# Verdict Execution time Memory Grader output
1 Incorrect 2 ms 2644 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2676 KB Output is correct
2 Correct 2 ms 2680 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2644 KB Output is correct
5 Correct 2 ms 2676 KB Output is correct
6 Correct 2 ms 2676 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2676 KB Output is correct
2 Correct 2 ms 2680 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2644 KB Output is correct
5 Correct 2 ms 2676 KB Output is correct
6 Correct 2 ms 2676 KB Output is correct
7 Correct 2 ms 2772 KB Output is correct
8 Correct 3 ms 2772 KB Output is correct
9 Correct 3 ms 2644 KB Output is correct
10 Correct 3 ms 2772 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct

Subtask #5
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2676 KB Output is correct
2 Correct 2 ms 2680 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2644 KB Output is correct
5 Correct 2 ms 2676 KB Output is correct
6 Correct 2 ms 2676 KB Output is correct
7 Correct 2 ms 2772 KB Output is correct
8 Correct 3 ms 2772 KB Output is correct
9 Correct 3 ms 2644 KB Output is correct
10 Correct 3 ms 2772 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct
12 Correct 59 ms 13736 KB Output is correct
13 Correct 66 ms 17764 KB Output is correct
14 Correct 38 ms 10300 KB Output is correct
15 Correct 71 ms 10424 KB Output is correct
16 Correct 52 ms 10532 KB Output is correct

Subtask #6
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2676 KB Output is correct
2 Correct 2 ms 2680 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2644 KB Output is correct
5 Correct 2 ms 2676 KB Output is correct
6 Correct 2 ms 2676 KB Output is correct
7 Correct 2 ms 2772 KB Output is correct
8 Correct 3 ms 2772 KB Output is correct
9 Correct 3 ms 2644 KB Output is correct
10 Correct 3 ms 2772 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct
12 Correct 1 ms 2644 KB Output is correct
13 Incorrect 2 ms 2644 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2676 KB Output is correct
2 Correct 2 ms 2680 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2644 KB Output is correct
5 Correct 2 ms 2676 KB Output is correct
6 Correct 2 ms 2676 KB Output is correct
7 Correct 2 ms 2772 KB Output is correct
8 Correct 3 ms 2772 KB Output is correct
9 Correct 3 ms 2644 KB Output is correct
10 Correct 3 ms 2772 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct
12 Correct 59 ms 13736 KB Output is correct
13 Correct 66 ms 17764 KB Output is correct
14 Correct 38 ms 10300 KB Output is correct
15 Correct 71 ms 10424 KB Output is correct
16 Correct 52 ms 10532 KB Output is correct
17 Correct 1 ms 2644 KB Output is correct
18 Incorrect 2 ms 2644 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #8
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Incorrect 2 ms 2644 KB Output isn't correct
3 Halted 0 ms 0 KB -