結果

問題 No.196 典型DP (1)
ユーザー ひばちひばち
提出日時 2020-05-28 00:00:17
言語 C#(csc)
(csc 3.9.0)
結果
AC  
実行時間 122 ms / 2,000 ms
コード長 9,641 bytes
コンパイル時間 1,187 ms
コンパイル使用メモリ 115,968 KB
実行使用メモリ 51,328 KB
最終ジャッジ日時 2024-10-13 03:54:57
合計ジャッジ時間 4,487 ms
ジャッジサーバーID
(参考情報)
judge3 / judge5
このコードへのチャレンジ
(要ログイン)
ファイルパターン 結果
sample AC * 3
other AC * 41
権限があれば一括ダウンロードができます
コンパイルメッセージ
Microsoft (R) Visual C# Compiler version 3.9.0-6.21124.20 (db94f4cc)
Copyright (C) Microsoft Corporation. All rights reserved.

ソースコード

diff #
プレゼンテーションモードにする

using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Runtime.CompilerServices;
using System.Text;
using System.Diagnostics;
using System.Numerics;
using static System.Console;
using static System.Convert;
using static System.Math;
using static Template;
using Pi = Pair<int, int>;
class Solver
{
int N, K;
List<int>[] g;
int[] cld;
ModInt[][] dp;
public void Solve(Scanner sc)
{
sc.Make(out N, out K);
cld = new int[N];
g = Create(N, () => new List<int>());
for (var i = 0; i < N-1; i++)
{
int a, b;
sc.Make(out a, out b);
g[a].Add(b);
g[b].Add(a);
}
chd(0, -1);
dp = new ModInt[N][];
calc(0, -1);
Console.WriteLine(dp[0][K]);
}
void chd(int i,int p)
{
foreach (var e in g[i])
{
if (e == p) continue;
chd(e, i);
cld[i] += cld[e];
}
cld[i]++;
}
void calc(int i,int p)
{
dp[i] = new ModInt[K+1];
dp[i][0] = 1;
if (cld[i] <= K) dp[i][cld[i]] = 1;
var now = 0;
foreach (var e in g[i])
{
if (e == p) continue;
calc(e, i);
for (int k = Min(K,now); k >= 0; k--)
for (int l = 1; l <= Min(K, cld[e]); l++)
if (k + l <= K)
dp[i][k+l] += dp[e][l] * dp[i][k];
now += cld[e];
}
}
}
public struct ModInt
{
public const long MOD = (int)1e9 + 7;
//public const long MOD = 998244353;
public long Value { get; set; }
public ModInt(long n = 0) { Value = n; }
private static ModInt[] fac;//i!
private static ModInt[] inv;//1/i
private static ModInt[] facinv;//1/(i!)
public override string ToString() => Value.ToString();
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ModInt operator +(ModInt l, ModInt r)
{
l.Value += r.Value;
if (l.Value >= MOD) l.Value -= MOD;
return l;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ModInt operator -(ModInt l, ModInt r)
{
l.Value -= r.Value;
if (l.Value < 0) l.Value += MOD;
return l;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ModInt operator *(ModInt l, ModInt r) => new ModInt(l.Value * r.Value % MOD);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ModInt operator /(ModInt l, ModInt r) => l * Pow(r, MOD - 2);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static implicit operator long(ModInt l) => l.Value;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static implicit operator ModInt(long n)
{
n %= MOD; if (n < 0) n += MOD;
return new ModInt(n);
}
public static ModInt Pow(ModInt m, long n)
{
if (n == 0) return 1;
if (n % 2 == 0) return Pow(m * m, n >> 1);
else return Pow(m * m, n >> 1) * m;
}
public static void Build(int n)
{
fac = new ModInt[n + 1];
facinv = new ModInt[n + 1];
inv = new ModInt[n + 1];
inv[1] = 1;
fac[0] = fac[1] = 1;
facinv[0] = facinv[1] = 1;
for (var i = 2; i <= n; i++)
{
fac[i] = fac[i - 1] * i;
inv[i] = MOD - inv[MOD % i] * (MOD / i);
facinv[i] = facinv[i - 1] * inv[i];
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ModInt Fac(ModInt n) => fac[n];
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ModInt Inv(ModInt n) => inv[n];
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ModInt FacInv(ModInt n) => facinv[n];
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static ModInt Comb(ModInt n, ModInt r)
{
if (n < r) return 0;
if (n == r) return 1;
var calc = fac[n];
calc = calc * facinv[r];
calc = calc * facinv[n - r];
return calc;
}
}
#region Template
public static class Template
{
static void Main(string[] args)
{
Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false });
new Solver().Solve(new Scanner());
Console.Out.Flush();
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static bool chmin<T>(ref T a, T b) where T : IComparable<T> { if (a.CompareTo(b) > 0) { a = b; return true; } return false; }
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static bool chmax<T>(ref T a, T b) where T : IComparable<T> { if (a.CompareTo(b) < 0) { a = b; return true; } return false; }
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static void swap<T>(ref T a, ref T b) { var t = b; b = a; a = t; }
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static void swap<T>(this IList<T> A, int i, int j) { var t = A[i]; A[i] = A[j]; A[j] = t; }
public static T[] Create<T>(int n, Func<T> f) { var rt = new T[n]; for (var i = 0; i < rt.Length; ++i) rt[i] = f(); return rt; }
public static T[] Create<T>(int n, Func<int, T> f) { var rt = new T[n]; for (var i = 0; i < rt.Length; ++i) rt[i] = f(i); return rt; }
public static IEnumerable<T> Shuffle<T>(this IEnumerable<T> A) => A.OrderBy(v => Guid.NewGuid());
public static int CompareTo<T>(this T[] A, T[] B, Comparison<T> cmp = null) { cmp = cmp ?? Comparer<T>.Default.Compare; for (var i = 0; i < Min(A
        .Length, B.Length); i++) { int c = cmp(A[i], B[i]); if (c > 0) return 1; else if (c < 0) return -1; } if (A.Length == B.Length) return 0; if
        (A.Length > B.Length) return 1; else return -1; }
public static int MaxElement<T>(this IList<T> A, Comparison<T> cmp = null) { cmp = cmp ?? Comparer<T>.Default.Compare; T max = A[0]; int rt = 0;
        for (int i = 1; i < A.Count; i++) if (cmp(max, A[i]) < 0) { max = A[i]; rt = i; } return rt; }
public static T PopBack<T>(this List<T> A) { var v = A[A.Count - 1]; A.RemoveAt(A.Count - 1); return v; }
public static void Fail<T>(T s) { Console.WriteLine(s); Console.Out.Close(); Environment.Exit(0); }
}
public class Scanner
{
public string Str => Console.ReadLine().Trim();
public int Int => int.Parse(Str);
public long Long => long.Parse(Str);
public double Double => double.Parse(Str);
public int[] ArrInt => Str.Split(' ').Select(int.Parse).ToArray();
public long[] ArrLong => Str.Split(' ').Select(long.Parse).ToArray();
public char[][] Grid(int n) => Create(n, () => Str.ToCharArray());
public int[] ArrInt1D(int n) => Create(n, () => Int);
public long[] ArrLong1D(int n) => Create(n, () => Long);
public int[][] ArrInt2D(int n) => Create(n, () => ArrInt);
public long[][] ArrLong2D(int n) => Create(n, () => ArrLong);
private Queue<string> q = new Queue<string>();
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public T Next<T>() { if (q.Count == 0) foreach (var item in Str.Split(' ')) q.Enqueue(item); return (T)Convert.ChangeType(q.Dequeue(), typeof(T
        )); }
public void Make<T1>(out T1 v1) => v1 = Next<T1>();
public void Make<T1, T2>(out T1 v1, out T2 v2) { v1 = Next<T1>(); v2 = Next<T2>(); }
public void Make<T1, T2, T3>(out T1 v1, out T2 v2, out T3 v3) { Make(out v1, out v2); v3 = Next<T3>(); }
public void Make<T1, T2, T3, T4>(out T1 v1, out T2 v2, out T3 v3, out T4 v4) { Make(out v1, out v2, out v3); v4 = Next<T4>(); }
public void Make<T1, T2, T3, T4, T5>(out T1 v1, out T2 v2, out T3 v3, out T4 v4, out T5 v5) { Make(out v1, out v2, out v3, out v4); v5 = Next<T5
        >(); }
public void Make<T1, T2, T3, T4, T5, T6>(out T1 v1, out T2 v2, out T3 v3, out T4 v4, out T5 v5, out T6 v6) { Make(out v1, out v2, out v3, out v4,
        out v5); v6 = Next<T6>(); }
public void Make<T1, T2, T3, T4, T5, T6, T7>(out T1 v1, out T2 v2, out T3 v3, out T4 v4, out T5 v5, out T6 v6, out T7 v7) { Make(out v1, out v2,
        out v3, out v4, out v5, out v6); v7 = Next<T7>(); }
//public (T1, T2) Make<T1, T2>() { Make(out T1 v1, out T2 v2); return (v1, v2); }
//public (T1, T2, T3) Make<T1, T2, T3>() { Make(out T1 v1, out T2 v2, out T3 v3); return (v1, v2, v3); }
//public (T1, T2, T3, T4) Make<T1, T2, T3, T4>() { Make(out T1 v1, out T2 v2, out T3 v3, out T4 v4); return (v1, v2, v3, v4); }
}
public class Pair<T1, T2> : IComparable<Pair<T1, T2>>
{
public T1 v1;
public T2 v2;
public Pair() { }
public Pair(T1 v1, T2 v2)
{ this.v1 = v1; this.v2 = v2; }
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int CompareTo(Pair<T1, T2> p)
{
var c = Comparer<T1>.Default.Compare(v1, p.v1);
if (c == 0)
c = Comparer<T2>.Default.Compare(v2, p.v2);
return c;
}
public override string ToString() => $"{v1.ToString()} {v2.ToString()}";
public void Deconstruct(out T1 a, out T2 b) { a = v1; b = v2; }
}
public class Pair<T1, T2, T3> : Pair<T1, T2>, IComparable<Pair<T1, T2, T3>>
{
public T3 v3;
public Pair() : base() { }
public Pair(T1 v1, T2 v2, T3 v3) : base(v1, v2)
{ this.v3 = v3; }
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public int CompareTo(Pair<T1, T2, T3> p)
{
var c = base.CompareTo(p);
if (c == 0)
c = Comparer<T3>.Default.Compare(v3, p.v3);
return c;
}
public override string ToString() => $"{base.ToString()} {v3.ToString()}";
public void Deconstruct(out T1 a, out T2 b, out T3 c) { Deconstruct(out a, out b); c = v3; }
}
#endregion
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