結果
| 問題 | No.196 典型DP (1) |
| ユーザー |
 紙ぺーぱー
|
| 提出日時 | 2015-04-26 22:56:29 |
| 言語 | C#(csc) (csc 3.9.0) |
| 結果 |
AC
|
| 実行時間 | 184 ms / 2,000 ms |
| コード長 | 6,290 bytes |
| コンパイル時間 | 1,095 ms |
| コンパイル使用メモリ | 118,596 KB |
| 実行使用メモリ | 40,448 KB |
| 最終ジャッジ日時 | 2024-07-05 03:14:55 |
| 合計ジャッジ時間 | 7,042 ms |
|
ジャッジサーバーID （参考情報） |
judge1 / judge2 |
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| ファイルパターン | 結果 |
|---|---|
| sample | AC * 3 |
| other | AC * 41 |
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
using System;
using System.Linq;
using System.Collections.Generic;
using Debug = System.Diagnostics.Debug;
using StringBuilder = System.Text.StringBuilder;
using System.Numerics;
namespace Program
{
public class Solver
{
public void Solve()
{
var n = sc.Integer();
var k = sc.Integer();
var G = Enumerate(n, x => new List<int>());
for (int i = 0; i < n - 1; i++)
{
var a = sc.Integer();
var b = sc.Integer();
G[a].Add(b);
G[b].Add(a);
}
var size = new int[n];
Func<int, int, int> dfs = null;
dfs = (prev, cur) =>
{
var s = 1;
foreach (var to in G[cur])
if (to != prev) s += dfs(cur, to);
return size[cur] = s;
};
dfs(-1, 0);
var cnt = new ModInteger[n + 1, n + 1];
Action<int, int> rec = null;
rec = (prev, cur) =>
{
var sz = size[cur];
cnt[cur, 0] = 1;
cnt[cur, sz] = 1;
var max = 0;
foreach (var to in G[cur])
{
if (prev == to)
continue;
rec(cur, to);
for (int i = max; i >= 0; i--)
{
for (int j = 1; j <= size[to]; j++)
{
cnt[cur, i + j] += cnt[cur, i] * cnt[to, j];
max = Math.Max(max, i + j);
}
}
}
};
rec(-1, 0);
IO.Printer.Out.WriteLine(cnt[0, k]);
}
public IO.StreamScanner sc = new IO.StreamScanner(Console.OpenStandardInput());
static T[] Enumerate<T>(int n, Func<int, T> f) { var a = new T[n]; for (int i = 0; i < n; ++i) a[i] = f(i); return a; }
static public void Swap<T>(ref T a, ref T b) { var tmp = a; a = b; b = tmp; }
}
}
#region Ex
namespace Program.IO
{
using System.IO;
using System.Text;
using System.Globalization;
public class Printer : StreamWriter
{
static Printer() { Out = new Printer(Console.OpenStandardOutput()) { AutoFlush = false }; }
public static Printer Out { get; set; }
public override IFormatProvider FormatProvider { get { return CultureInfo.InvariantCulture; } }
public Printer(System.IO.Stream stream) : base(stream, new UTF8Encoding(false, true)) { }
public Printer(System.IO.Stream stream, Encoding encoding) : base(stream, encoding) { }
public void Write<T>(string format, IEnumerable<T> source) { base.Write(format, source.OfType<object>().ToArray()); }
public void WriteLine<T>(string format, IEnumerable<T> source) { base.WriteLine(format, source.OfType<object>().ToArray()); }
}
public class StreamScanner
{
public StreamScanner(Stream stream) { str = stream; }
public readonly Stream str;
private readonly byte[] buf = new byte[1024];
private int len, ptr;
public bool isEof = false;
public bool IsEndOfStream { get { return isEof; } }
private byte read()
{
if (isEof) return 0;
if (ptr >= len) { ptr = 0; if ((len = str.Read(buf, 0, 1024)) <= 0) { isEof = true; return 0; } }
return buf[ptr++];
}
public char Char() { byte b = 0; do b = read(); while (b < 33 || 126 < b); return (char)b; }
public string Scan()
{
var sb = new StringBuilder();
for (var b = Char(); b >= 33 && b <= 126; b = (char)read())
sb.Append(b);
return sb.ToString();
}
public long Long()
{
if (isEof) return long.MinValue;
long ret = 0; byte b = 0; var ng = false;
do b = read();
while (b != '-' && (b < '0' || '9' < b));
if (b == '-') { ng = true; b = read(); }
for (; true; b = read())
{
if (b < '0' || '9' < b)
return ng ? -ret : ret;
else ret = ret * 10 + b - '0';
}
}
public int Integer() { return (isEof) ? int.MinValue : (int)Long(); }
public double Double() { return double.Parse(Scan(), CultureInfo.InvariantCulture); }
private T[] enumerate<T>(int n, Func<T> f)
{
var a = new T[n];
for (int i = 0; i < n; ++i) a[i] = f();
return a;
}
public char[] Char(int n) { return enumerate(n, Char); }
public string[] Scan(int n) { return enumerate(n, Scan); }
public double[] Double(int n) { return enumerate(n, Double); }
public int[] Integer(int n) { return enumerate(n, Integer); }
public long[] Long(int n) { return enumerate(n, Long); }
}
}
static class Ex
{
static public string AsString(this IEnumerable<char> ie) { return new string(System.Linq.Enumerable.ToArray(ie)); }
static public string AsJoinedString<T>(this IEnumerable<T> ie, string st = " ") { return string.Join(st, ie); }
static public void Main()
{
var solver = new Program.Solver();
solver.Solve();
Program.IO.Printer.Out.Flush();
}
}
#endregion
#region ModNumber
public partial struct ModInteger
{
public const long Mod = (long)1e9 + 7;
public long num;
public ModInteger(long n) : this() { num = n % Mod; }
public override string ToString() { return num.ToString(); }
public static ModInteger operator +(ModInteger l, ModInteger r) { var n = l.num + r.num; if (n >= Mod)n -= Mod; return new ModInteger(n); }
public static ModInteger operator -(ModInteger l, ModInteger r) { var n = l.num - r.num; if (n < 0)n += Mod; return new ModInteger(n); }
public static ModInteger operator *(ModInteger l, ModInteger r) { return new ModInteger((l.num * r.num) % Mod); }
public static implicit operator ModInteger(long n) { return new ModInteger(n); }
}
#endregion