結果

問題 No.1227 I hate ThREE
ユーザー heno239heno239
提出日時 2020-09-11 23:38:32
言語 C++14
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 81 ms / 2,000 ms
コード長 3,879 bytes
コンパイル時間 1,435 ms
コンパイル使用メモリ 119,008 KB
実行使用メモリ 27,124 KB
最終ジャッジ日時 2023-08-30 14:51:20
合計ジャッジ時間 3,651 ms
ジャッジサーバーID
（参考情報） 		judge14 / judge12
このコードへのチャレンジ
（要ログイン）

テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 5 ms
11,680 KB
testcase_01 AC 5 ms
11,704 KB
testcase_02 AC 5 ms
11,652 KB
testcase_03 AC 6 ms
11,904 KB
testcase_04 AC 5 ms
11,684 KB
testcase_05 AC 6 ms
11,616 KB
testcase_06 AC 5 ms
11,584 KB
testcase_07 AC 5 ms
11,576 KB
testcase_08 AC 8 ms
11,700 KB
testcase_09 AC 7 ms
11,736 KB
testcase_10 AC 6 ms
11,740 KB
testcase_11 AC 26 ms
11,816 KB
testcase_12 AC 28 ms
11,848 KB
testcase_13 AC 5 ms
11,676 KB
testcase_14 AC 6 ms
11,800 KB
testcase_15 AC 9 ms
11,824 KB
testcase_16 AC 13 ms
11,856 KB
testcase_17 AC 10 ms
11,772 KB
testcase_18 AC 17 ms
11,744 KB
testcase_19 AC 14 ms
12,056 KB
testcase_20 AC 18 ms
11,744 KB
testcase_21 AC 5 ms
11,908 KB
testcase_22 AC 15 ms
11,808 KB
testcase_23 AC 77 ms
26,504 KB
testcase_24 AC 78 ms
21,864 KB
testcase_25 AC 81 ms
27,124 KB
testcase_26 AC 27 ms
11,752 KB
testcase_27 AC 28 ms
12,012 KB
testcase_28 AC 29 ms
11,788 KB
testcase_29 AC 29 ms
11,904 KB
testcase_30 AC 28 ms
11,760 KB
testcase_31 AC 27 ms
11,748 KB
testcase_32 AC 29 ms
11,768 KB
testcase_33 AC 27 ms
11,732 KB
testcase_34 AC 28 ms
12,008 KB
testcase_35 AC 28 ms
11,748 KB
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<utility>
#include<cassert>
#include<complex>
#include<numeric>
#include<array>
//#include<atcoder/dsu>
//#include<atcoder/fenwicktree>
//#include<atcoder/math>
//#include<atcoder/maxflow>

using namespace std;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
constexpr ll mod = 1000000007;
const ll INF = mod * mod;
typedef pair<int, int>P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;
typedef long double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-8;
const ld pi = acosl(-1.0);

ll mod_pow(ll x, ll n, ll m = mod) {
	if (x >= m)x %= m;
	ll res = 1;
	while (n) {
		if (n & 1)res = res * x % m;
		x = x * x % m; n >>= 1;
	}
	return res;
}
struct modint {
	ll n;
	modint() :n(0) { ; }
	modint(ll m) :n(m) {
		if (n >= mod)n %= mod;
		else if (n < 0)n = (n % mod + mod) % mod;
	}
	operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
modint operator+=(modint& a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= mod; return a; }
modint operator-=(modint& a, modint b) { a.n -= b.n; if (a.n < 0)a.n += mod; return a; }
modint operator*=(modint& a, modint b) { a.n = ((ll)a.n * b.n) % mod; return a; }
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, ll n) {
	if (n == 0)return modint(1);
	modint res = (a * a) ^ (n / 2);
	if (n % 2)res = res * a;
	return res;
}

ll inv(ll a, ll p) {
	return (a == 1 ? 1 : (1 - p * inv(p % a, a)) / a + p);
}
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }

const int max_n = 1 << 19;
modint fact[max_n], factinv[max_n];
void init_f() {
	fact[0] = modint(1);
	for (int i = 0; i < max_n - 1; i++) {
		fact[i + 1] = fact[i] * modint(i + 1);
	}
	factinv[max_n - 1] = modint(1) / fact[max_n - 1];
	for (int i = max_n - 2; i >= 0; i--) {
		factinv[i] = factinv[i + 1] * modint(i + 1);
	}
}
modint comb(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[b] * factinv[a - b];
}

ll gcd(ll a, ll b) {
	if (a < b)swap(a, b);
	while (b) {
		ll r = a % b; a = b; b = r;
	}
	return a;
}

int n;

vector<int> G[1000];

int sz;
vector<modint> dfs(int id, int fr) {
	vector<modint> res;
	res.resize(min(sz, 2 * n),1);
	for (int to : G[id])if (to != fr) {
		vector<modint> nex = dfs(to, id);
		vector<modint> cop = res;
		fill(all(res), 0);
		rep(i, res.size()) {
			modint s = 0;
			if (i > 0)s += nex[i - 1];
			if (i + 1 < res.size())s += nex[i + 1];
			res[i] = s * cop[i];
		}
	}
	return res;
}

modint calc(int s) {
	sz = s;
	vector<modint> z = dfs(0, -1);
	modint res = 0;
	if (sz > 2 * n) {
		rep(i, n)res += z[i]; res *= 2;
		res += (sz - (2 * n)) * mod_pow(2, n - 1);
	}
	else {
		rep(i, z.size())res += z[i];
	}
	return res;
}
void solve() {
	int c; cin >> n >> c;
	rep(i, n - 1) {
		int a, b; cin >> a >> b; a--; b--;
		G[a].push_back(b);
		G[b].push_back(a);
	}

	modint ans = 0;
	int cnt[3] = {c/3,(c+1)/3,(c+2)/3 };
	rep(i, 3) {
		ans += calc(cnt[i]);
	}
	cout << ans << "\n";
}

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	//cout << fixed << setprecision(15);
	//init_f();
	//init();
	//expr();
	//int t; cin >> t; rep(i, t)
	solve();
	return 0;
}
0