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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#213633#2715. 8.4t4STASISZHY2053ms1396kbC++111.4kb2024-11-12 22:13:572024-11-12 23:59:24

answer

// Problem: B. 8.4t4
// Contest: undefined - NOIP2024训练赛 03
// URL: http://119.28.3.174/contest/1155/problem/2715
// Memory Limit: 1024 MB
// Time Limit: 1000 ms
// 
// Powered by CP Editor (https://cpeditor.org)

#include<bits/stdc++.h>
//#define int long long
#define fi first
#define se second
#define PII pair<int, int>

using namespace std;

const int N = 2e5 + 10, M = 1e6 + 10, INF = 0x3f3f3f3f;

const int mod=1e9+7;
const int maxn=5005;
bool vis[maxn];
vector<int> e[maxn];
int n;
inline void view_all(vector<int> &cur,int x,int fa)
{
    cur.push_back(x);
    for(int p : e[x])
    {
        if (vis[p]) continue;
        if (p == fa) continue;
        view_all(cur, p, x);
    }
}
inline int calc(int x)
{
    vector<int> cur;
    int ans = 0;
    view_all(cur, x, -1);
    for(auto w : cur)
    {
        int res = 1;
        vis[w] = 1;
        for(auto p: e[w])
        {
            if (vis[p]) continue;
            res = 1ll * res * calc(p) % mod;
        }
        vis[w] = 0;
        ans = (ans + res) % mod;
    }
    return ans;
}
inline int get_ans()
{
    return calc(1);
}

// int n, m, q, ans;
// int s[N], dp[N];

// vector<int> e[N];

signed main()
{
	ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	cin >> n;
	for(int i = 1; i < n; i ++)
	{
		int u, v; cin >> u >> v;
		e[u].push_back(v), e[v].push_back(u);
		
	}
	cout << get_ans() << '\n';
	return 0;
}

详细

小提示:点击横条可展开更详细的信息

Test #1:

score: 10
Accepted
time: 41ms
memory: 1396kb

input:

10
1 2
1 3
3 4
3 5
3 6
3 7
1 8
5 9
5 10

output:

227506

result:

ok found '227506.00000', expected '227506.00000', error '0.00000'

Test #2:

score: 10
Accepted
time: 12ms
memory: 1396kb

input:

10
1 2
1 3
3 4
4 5
5 6
4 7
5 8
8 9
8 10

output:

70140

result:

ok found '70140.00000', expected '70140.00000', error '0.00000'

Test #3:

score: 0
Time Limit Exceeded

input:

100
1 2
1 3
1 4
3 5
5 6
4 7
7 8
8 9
8 10
3 11
7 12
1 13
5 14
8 15
10 16
7 17
1 18
6 19
10 20
15 21
7...

output:


result:


Test #4:

score: 0
Time Limit Exceeded

input:

100
1 2
2 3
3 4
4 5
4 6
6 7
5 8
8 9
8 10
1 11
6 12
4 13
9 14
13 15
7 16
3 17
15 18
17 19
9 20
8 21
4...

output:


result:


Test #5:

score: 0
Time Limit Exceeded

input:

100
1 2
2 3
3 4
2 5
2 6
5 7
2 8
4 9
7 10
5 11
11 12
6 13
8 14
13 15
5 16
11 17
16 18
11 19
7 20
19 2...

output:


result:


Test #6:

score: 0
Time Limit Exceeded

input:

500
1 2
1 3
3 4
3 5
5 6
1 7
3 8
8 9
4 10
6 11
7 12
2 13
11 14
8 15
7 16
9 17
2 18
3 19
15 20
2 21
20...

output:


result:


Test #7:

score: 0
Time Limit Exceeded

input:

500
1 2
1 3
1 4
2 5
5 6
5 7
4 8
8 9
1 10
4 11
8 12
6 13
13 14
13 15
12 16
1 17
10 18
13 19
1 20
1 21...

output:


result:


Test #8:

score: 0
Time Limit Exceeded

input:

5000
1 2
1 3
1 4
3 5
3 6
5 7
4 8
4 9
1 10
5 11
6 12
10 13
12 14
14 15
12 16
8 17
14 18
9 19
8 20
20 ...

output:


result:


Test #9:

score: 0
Time Limit Exceeded

input:

5000
1 2
1 3
1 4
2 5
1 6
5 7
2 8
5 9
4 10
9 11
10 12
8 13
7 14
13 15
12 16
5 17
9 18
8 19
3 20
4 21
...

output:


result:


Test #10:

score: 0
Time Limit Exceeded

input:

5000
1 2
1 3
1 4
4 5
4 6
3 7
2 8
8 9
6 10
9 11
3 12
3 13
7 14
13 15
4 16
10 17
9 18
10 19
5 20
17 21...

output:


result: