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Submission #578502

# Submission time Handle Problem Language Result Execution time Memory
578502 2022-06-17T06:29:01 Z amunduzbaev Star Trek (CEOI20_startrek) C++17
38 / 100
 64 ms 17468 KB 
#include "bits/stdc++.h"
using namespace std;
 
#define ar array
typedef int64_t ll;
 
const int N = 1e5 + 5;
const int mod = 1e9 + 7;
vector<int> edges[N];
int dp[N], up[N], cnt[N], n;
int sub[N], rev[N], tot[N], tmp[N];

void dfs(int u, int p = -1){
	for(auto x : edges[u]){
		if(x == p) continue;
		dfs(x, u);
		if(dp[x] == 0){
			dp[u] = 1, 
			tmp[u] += sub[x], 
			cnt[u]++;
		} 
		
		tot[u] += sub[x];
	}
	
	if(cnt[u] > 1) sub[u] = 0;
	if(cnt[u] == 1) sub[u] = tmp[u];
	if(cnt[u] == 0) sub[u] = tot[u] + 1;
}

void re(int u, int p = -1){
	tot[u] += rev[u];
	if(up[u] == 0){
		tmp[u] += rev[u];
		dp[u] = 1, cnt[u]++;
	}
	if(cnt[u] > 1) sub[u] = 0;
	if(cnt[u] == 1) sub[u] = tmp[u];
	if(cnt[u] == 0) sub[u] = tot[u] + 1;
	
	for(auto x : edges[u]){
		if(x == p) continue;
		tot[u] -= sub[x];
		if(!dp[x]){
			cnt[u]--, tmp[u] -= sub[x];
		}
		
		if(cnt[u]) up[x] = 1;
		if(cnt[u] > 1) rev[x] = 0;
		if(cnt[u] == 1) rev[x] = tmp[u];
		if(cnt[u] == 0) rev[x] = tot[u] + 1;
		
		tot[u] += sub[x];
		if(!dp[x]){
			cnt[u]++, tmp[u] += sub[x];
		}
		
		re(x, u);
	}
}

signed main(){
	ios::sync_with_stdio(0); cin.tie(0);
	
	int d; cin>>n>>d;
	for(int i=1;i<n;i++){
		int a, b; cin>>a>>b;
		edges[a].push_back(b);
		edges[b].push_back(a);
	}
	
	dfs(1);
	up[1] = 1;
	re(1);
	int E = 0, L = 0;
	for(int i=1;i<=n;i++){
		if(dp[i] == 1) E = (E + sub[i]) % mod;
		else E = (E - sub[i] + mod) % mod, L++;
	}
	
	//~ for(int i=1;i<=n;i++){
		//~ cout<<sub[i]<<" ";
	//~ } cout<<"\n";
	
	
	vector<int> e(d + 1), f(d + 1);
	e[0] = f[0] = 1;
	for(int i=1;i<=d;i++){
		e[i] = e[i-1] * 1ll * E % mod;
		f[i] = f[i-1] * 1ll * n % mod * n % mod;
	}
	
	d--;
	int res = 0;
	for(int i=0;i<=d;i++){
		res = (res + f[d-i] * 1ll * e[i]) % mod;
	}
	res = res * 1ll * L % mod;
	if(dp[1]){
		res = res * 1ll * sub[1] % mod;
	} else {
		res = (f[d + 1] - res * 1ll * sub[1] % mod + mod) % mod;
	}
	res = (f[d + 1] - res) % mod;
	cout<<res<<"\n";
}
 
/*
 
5 1
1 2
2 3
2 4
1 5
 
*/

Subtask #1
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 3 ms 2772 KB Output is correct

Subtask #2
0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 3 ms 2676 KB Output is correct
3 Runtime error 5 ms 5232 KB Execution killed with signal 11
4 Halted 0 ms 0 KB -

Subtask #3
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 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 2672 KB Output is correct
6 Correct 2 ms 2672 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 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 2672 KB Output is correct
6 Correct 2 ms 2672 KB Output is correct
7 Correct 2 ms 2760 KB Output is correct
8 Correct 2 ms 2772 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 3 ms 2680 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 2644 KB Output is correct
2 Correct 2 ms 2644 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 2672 KB Output is correct
6 Correct 2 ms 2672 KB Output is correct
7 Correct 2 ms 2760 KB Output is correct
8 Correct 2 ms 2772 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 3 ms 2680 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct
12 Correct 57 ms 13260 KB Output is correct
13 Correct 64 ms 17468 KB Output is correct
14 Correct 45 ms 9596 KB Output is correct
15 Correct 62 ms 9728 KB Output is correct
16 Correct 55 ms 9732 KB Output is correct

Subtask #6
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 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 2672 KB Output is correct
6 Correct 2 ms 2672 KB Output is correct
7 Correct 2 ms 2760 KB Output is correct
8 Correct 2 ms 2772 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 3 ms 2680 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct
12 Correct 2 ms 2676 KB Output is correct
13 Correct 2 ms 2692 KB Output is correct
14 Correct 2 ms 2644 KB Output is correct
15 Correct 2 ms 2772 KB Output is correct
16 Correct 2 ms 2644 KB Output is correct
17 Correct 2 ms 2644 KB Output is correct
18 Correct 2 ms 2676 KB Output is correct
19 Correct 2 ms 2644 KB Output is correct
20 Correct 2 ms 2644 KB Output is correct
21 Correct 2 ms 2712 KB Output is correct
22 Correct 2 ms 2812 KB Output is correct
23 Correct 2 ms 2676 KB Output is correct
24 Correct 2 ms 2644 KB Output is correct
25 Correct 2 ms 2644 KB Output is correct
26 Correct 4 ms 3412 KB Output is correct
27 Correct 4 ms 3540 KB Output is correct
28 Incorrect 4 ms 3540 KB Output isn't correct
29 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 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 2672 KB Output is correct
6 Correct 2 ms 2672 KB Output is correct
7 Correct 2 ms 2760 KB Output is correct
8 Correct 2 ms 2772 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 3 ms 2680 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct
12 Correct 57 ms 13260 KB Output is correct
13 Correct 64 ms 17468 KB Output is correct
14 Correct 45 ms 9596 KB Output is correct
15 Correct 62 ms 9728 KB Output is correct
16 Correct 55 ms 9732 KB Output is correct
17 Correct 2 ms 2676 KB Output is correct
18 Correct 2 ms 2692 KB Output is correct
19 Correct 2 ms 2644 KB Output is correct
20 Correct 2 ms 2772 KB Output is correct
21 Correct 2 ms 2644 KB Output is correct
22 Correct 2 ms 2644 KB Output is correct
23 Correct 2 ms 2676 KB Output is correct
24 Correct 2 ms 2644 KB Output is correct
25 Correct 2 ms 2644 KB Output is correct
26 Correct 2 ms 2712 KB Output is correct
27 Correct 2 ms 2812 KB Output is correct
28 Correct 2 ms 2676 KB Output is correct
29 Correct 2 ms 2644 KB Output is correct
30 Correct 2 ms 2644 KB Output is correct
31 Correct 4 ms 3412 KB Output is correct
32 Correct 4 ms 3540 KB Output is correct
33 Incorrect 4 ms 3540 KB Output isn't correct
34 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 Correct 3 ms 2772 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 3 ms 2676 KB Output is correct
5 Runtime error 5 ms 5232 KB Execution killed with signal 11
6 Halted 0 ms 0 KB -