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Submission #390078

# Submission time Handle Problem Language Result Execution time Memory
390078 2021-04-15T10:04:02 Z talant117408 Star Trek (CEOI20_startrek) C++17
30 / 100
 1000 ms 14744 KB 
/*
    Code written by Talant I.D.
*/
#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;
 
#define precision(n) fixed << setprecision(n)
#define pb push_back
#define ub upper_bound
#define lb lower_bound
#define mp make_pair
#define eps (double)1e-9
#define PI 2*acos(0.0)
#define endl "\n"
#define sz(v) int((v).size())
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
#define do_not_disturb ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define OK cout << "OK" << endl;
 
const int mod = 1e9+7;
 
ll mode(ll a) {
    a %= mod;
    if (a < 0) a += mod;
    return a;
}
 
ll subt(ll a, ll b) {
    return mode(mode(a)-mode(b));
}
 
ll add(ll a, ll b) {
    return mode(mode(a)+mode(b));
}
 
ll mult(ll a, ll b) {
    return mode(mode(a)*mode(b));
}
 
ll binpow(ll a, ll b) {
    ll res = 1;
    while (b) {
        if (b&1) res = mult(res, a);
        a = mult(a, a);
        b >>= 1;
    }
    return res;
}

const int N = 1e5+7;
int state[N];
int losing_children[N], critical, depth[N], par[N];
vector <int> graph[N];

bool dfs(int v, int p) {
	par[v] = p;
	depth[v] = depth[p]+1;
	int cnt = 0, children = 0;
	for (auto to : graph[v]) {
		if (to == p) continue;
		children++;
		dfs(to, v);
		cnt += (state[to] ? 1 : 0);
		if (state[to]) losing_children[v]++;
	}
	if (children == 0) state[v] = 1;
	else if (cnt) state[v] = 0;
	else state[v] = 1;
	return state[v];
}

void dfs2(int v, int p, int cnt = 0) {
	if (cnt == depth[v] && state[v]) critical++;
	if (state[v]) {
		for (auto to : graph[v]) {
			if (to == p) continue;
			dfs2(to, v, cnt+1);
		}
	}
	else {
		for (auto to : graph[v]) {
			if (to == p) continue;
			if (state[to]) {
				dfs2(to, v, (losing_children[v] == 1 ? cnt+1 : 0));
			}
		}
	}
}

int main() {
	do_not_disturb
	
	int n;
	ll d;
	cin >> n >> d;
	for (int i = 0; i < n-1; i++) {
		int x, y;
		cin >> x >> y;
		graph[x].pb(y);
		graph[y].pb(x);
	}
	
	if (n == 2) {
		cout << binpow(2, d*2);
	}
	else if (d == 1) {
		depth[1] = -1;
		dfs(1, 1);
		dfs2(1, 1);
		ll l = 0, w = 0;
		for (int i = 1; i <= n; i++) {
			for (int j = 1; j <= n; j++) losing_children[j] = 0;
			depth[i] = -1;
			dfs(i, i);
			if (state[i]) l++;
			else w++;
		}
		depth[1] = -1;
		dfs(1, 1);
		if (state[1]) cout << critical*l;
		else cout << n*w+(n-critical)*l;
	}
	
    return 0;
}

Subtask #1
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Incorrect 2 ms 2636 KB Output isn't correct

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2668 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Correct 2 ms 2636 KB Output is correct

Subtask #3
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Correct 3 ms 2636 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Correct 3 ms 2636 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct
7 Correct 23 ms 2784 KB Output is correct
8 Correct 25 ms 2816 KB Output is correct
9 Correct 20 ms 2764 KB Output is correct
10 Correct 21 ms 2748 KB Output is correct
11 Correct 21 ms 2680 KB Output is correct

Subtask #5
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Correct 3 ms 2636 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct
7 Correct 23 ms 2784 KB Output is correct
8 Correct 25 ms 2816 KB Output is correct
9 Correct 20 ms 2764 KB Output is correct
10 Correct 21 ms 2748 KB Output is correct
11 Correct 21 ms 2680 KB Output is correct
12 Execution timed out 1098 ms 14744 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #6
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Correct 3 ms 2636 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct
7 Correct 23 ms 2784 KB Output is correct
8 Correct 25 ms 2816 KB Output is correct
9 Correct 20 ms 2764 KB Output is correct
10 Correct 21 ms 2748 KB Output is correct
11 Correct 21 ms 2680 KB Output is correct
12 Correct 2 ms 2668 KB Output is correct
13 Incorrect 2 ms 2636 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 2636 KB Output is correct
2 Correct 2 ms 2636 KB Output is correct
3 Correct 2 ms 2636 KB Output is correct
4 Correct 2 ms 2636 KB Output is correct
5 Correct 3 ms 2636 KB Output is correct
6 Correct 2 ms 2636 KB Output is correct
7 Correct 23 ms 2784 KB Output is correct
8 Correct 25 ms 2816 KB Output is correct
9 Correct 20 ms 2764 KB Output is correct
10 Correct 21 ms 2748 KB Output is correct
11 Correct 21 ms 2680 KB Output is correct
12 Execution timed out 1098 ms 14744 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #8
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2636 KB Output is correct
2 Incorrect 2 ms 2636 KB Output isn't correct