結果

問題 No.93 ペガサス
ユーザー 紙ぺーぱー
提出日時 2016-05-26 21:32:36
言語 C#(csc)
(csc 3.9.0)
結果
AC  
実行時間 375 ms / 5,000 ms
コード長 7,579 bytes
コンパイル時間 1,032 ms
コンパイル使用メモリ 121,604 KB
実行使用メモリ 34,560 KB
最終ジャッジ日時 2024-10-07 16:17:55
合計ジャッジ時間 4,150 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 4
other AC * 16
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.Linq;
using System.Collections.Generic;
using Debug = System.Diagnostics.Debug;
using StringBuilder = System.Text.StringBuilder;
using System.Numerics;
using Number = System.Int64;
namespace Program
{
    public class Solver
    {
        public void Solve()
        {
            var n = sc.Integer();
            if (n <= 3)
            {
                var ans = new int[] { 0, 1, 2, 2 };
                IO.Printer.Out.WriteLine(ans[n]);
                return;
            }
            //dp[i,j,k]= i個攻撃関係，1個上が攻撃しているか，2個上が攻撃しているか
            var dp = new ModInteger[3, 2, 2];
            dp[0, 0, 0] = 2;
            dp[1, 1, 0] = 4;
            for (int m = 4; m <= n; m++)
            {
                var next = new ModInteger[m, 2, 2];
                for (int i = 0; i < m - 1; i++)
                {
                    for (int j = 0; j < 2; j++)
                    {
                        if ((dp[i, j, 0] + dp[i, j, 1]).num == 0) continue;
                        //攻撃する
                        next[i + 1, 1, j] += 2 * dp[i, j, 0];
                        next[i + 1, 1, j] += dp[i, j, 1];
                        //攻撃しつつキャンセルする
                        next[i, 1, j] += dp[i, j, 1];
                        //キャンセルする
                        if (i > 0)
                        {
                            if (j == 0)
                            {
                                next[i - 1, 0, j] += i * dp[i, j, 0];
                                next[i - 1, 0, j] += (i - 1) * dp[i, j, 1];
                            }
                            else
                            {
                                next[i - 1, 0, j] += (i - 1) * dp[i, j, 0];
                                next[i - 1, 0, j] += (i - 2) * dp[i, j, 1];
                                next[i - 1, 0, 0] += dp[i, j, 0];
                                next[i - 1, 0, 0] += dp[i, j, 1];
                            }
                        }
                        //キャンセルしないように置く
                        next[i, 0, j] += (m - 2 - i) * dp[i, j, 0];
                        next[i, 0, j] += (m - 2 - (i - 1)) * dp[i, j, 1];
                    }
                }
                dp = next;
            }
            IO.Printer.Out.WriteLine(dp[0, 0, 0]);
        }
        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 main
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 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, T[] source) { base.Write(format, source.OfType<object>().ToArray()); }
        public void WriteLine<T>(string format, 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) && !isEof); 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 string ScanLine()
        {
            var sb = new StringBuilder();
            for (var b = Char(); b != '\n'; b = (char)read())
                if (b == 0) break;
                else if (b != '\r') 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 != 0 && b != '-' && (b < '0' || '9' < b));
            if (b == 0) return long.MinValue;
            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() { var s = Scan(); return s != "" ? double.Parse(s, CultureInfo.InvariantCulture) : double.NaN; }
        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); }
    }
}
#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; if (num < 0) num += 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() { num = 
        n }; }
    public static ModInteger operator -(ModInteger l, ModInteger r) { var n = l.num + Mod - r.num; if (n >= Mod) n -= Mod; return new ModInteger() { 
        num = n }; }
    public static ModInteger operator *(ModInteger l, ModInteger r) { return new ModInteger(l.num * r.num); }
    public static ModInteger operator ^(ModInteger l, long r) { return ModInteger.Pow(l, r); }
    public static implicit operator ModInteger(long n) { return new ModInteger(n); }
    public static ModInteger Pow(ModInteger v, long k)
    {
        ModInteger ret = 1;
        var n = k;
        for (; n > 0; n >>= 1, v *= v)
        {
            if ((n & 1) == 1)
                ret = ret * v;
        }
        return ret;
    }
}
#endregion
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