#393463 (C#(csc)) No.916 Encounter On A Tree

• 問題: No.916 Encounter On A Tree
• ユーザー: EmKjp
• 提出日時: 2019-10-25 22:40:25
• 言語: C#(csc) (csc 3.9.0)
• 結果: WA
• 実行時間: -
• コード長: 5,701 bytes
• コンパイル時間: 2,471 ms
• コンパイル使用メモリ: 112,144 KB
• 実行使用メモリ: 33,940 KB
• 最終ジャッジ日時: 2024-09-13 05:28:15
• 合計ジャッジ時間: 6,352 ms
• ジャッジサーバーID （参考情報）: judge2 / judge4

ファイルパターン	結果
sample	AC * 5
other	AC * 52 WA * 4

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.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;

using E = System.Linq.Enumerable;

internal partial class Solver {
    const int mod = 1000000000 + 7;

    private int GetDepth(int x) {
        for (int depth = 1; depth < 30; depth++) {
            var lower = 1 << (depth - 1);
            var upper = lower * 2;
            if (lower <= x && x < upper) return depth;
        }
        throw new Exception();
    }
    public void Run() {
        var d = ni();
        var l = ni();
        var r = ni();
        var k = ni();

        var depthL = GetDepth(l) - 1;
        var depthR = GetDepth(r) - 1;

        var diff = Math.Abs(depthL - depthR);
        var fact = new long[(1 << d) + 10];
        fact[0] = fact[1] = 1;
        for (int i = 2; i < fact.Length; i++) {
            fact[i] = fact[i - 1] * i % mod;
        }

        long choose = 1;

        for (int i = 0; i < d; i++) {
            var p = 1 << i;
            if (depthL == i) p--;
            if (depthR == i) p--;
            choose *= fact[p];
            choose %= mod;
        }
        long ans = 0;
        if ((k - diff) >= 0 && (k - diff) % 2 == 0) {
            var x = (k - diff) / 2;

            //new { x, diff }.Dump();
            var lcpDepth = Math.Min(depthL, depthR) - x;
            if (x == 0) {
                ans = choose;
                ans *= 1 << lcpDepth;
                ans %= mod;
                ans *= 1 << diff;
                ans %= mod;
            } else {
                ans = 2 * choose;
                ans %= mod;
                ans *= 1 << lcpDepth;
                ans %= mod;
                var freeDepthL = Math.Max(x - 1, 0);
                var freeDepthR = Math.Max(x + diff - 1, 0);
                ans *= 1L << freeDepthL;
                ans %= mod;
                ans *= 1L << freeDepthR;
                ans %= mod;
            }
        }

        cout.WriteLine(ans);
    }
}

// PREWRITEN CODE BEGINS FROM HERE
internal partial class Solver : Scanner {
    public static void Main(string[] args) {
#if LOCAL
        new Solver(Console.In, Console.Out).Run();
#else
        Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false });
        new Solver(Console.In, Console.Out).Run();
        Console.Out.Flush();
#endif
    }

#pragma warning disable IDE0052
    private readonly TextReader cin;
    private readonly TextWriter cout;
#pragma warning restore IDE0052

    public Solver(TextReader reader, TextWriter writer)
        : base(reader) {
        cin = reader;
        cout = writer;
    }
    public Solver(string input, TextWriter writer)
        : this(new StringReader(input), writer) {
    }

#pragma warning disable IDE1006
#pragma warning disable IDE0051
    private int ni() { return NextInt(); }
    private int[] ni(int n) { return NextIntArray(n); }
    private long nl() { return NextLong(); }
    private long[] nl(int n) { return NextLongArray(n); }
    private double nd() { return NextDouble(); }
    private double[] nd(int n) { return NextDoubleArray(n); }
    private string ns() { return Next(); }
    private string[] ns(int n) { return NextArray(n); }
#pragma warning restore IDE1006
#pragma warning restore IDE0051
}

internal static class LinqPadExtension {
    public static T Dump<T>(this T obj) {
#if LOCAL
        return LINQPad.Extensions.Dump(obj);
#else
        return obj;
#endif
    }
}

public class Scanner {
    private readonly TextReader Reader;
    private readonly Queue<string> TokenQueue = new Queue<string>();
    private readonly CultureInfo ci = CultureInfo.InvariantCulture;

    public Scanner()
        : this(Console.In) {
    }

    public Scanner(TextReader reader) {
        Reader = reader;
    }

    public int NextInt() { return int.Parse(Next(), ci); }
    public long NextLong() { return long.Parse(Next(), ci); }
    public double NextDouble() { return double.Parse(Next(), ci); }
    public string[] NextArray(int size) {
        string[] array = new string[size];
        for (int i = 0; i < size; i++) {
            array[i] = Next();
        }

        return array;
    }
    public int[] NextIntArray(int size) {
        int[] array = new int[size];
        for (int i = 0; i < size; i++) {
            array[i] = NextInt();
        }

        return array;
    }

    public long[] NextLongArray(int size) {
        long[] array = new long[size];
        for (int i = 0; i < size; i++) {
            array[i] = NextLong();
        }

        return array;
    }

    public double[] NextDoubleArray(int size) {
        double[] array = new double[size];
        for (int i = 0; i < size; i++) {
            array[i] = NextDouble();
        }

        return array;
    }

    public string Next() {
        if (TokenQueue.Count == 0) {
            if (!StockTokens()) {
                throw new InvalidOperationException();
            }
        }
        return TokenQueue.Dequeue();
    }

    public bool HasNext() {
        if (TokenQueue.Count > 0) {
            return true;
        }

        return StockTokens();
    }

    private static readonly char[] _separator = new[] { ' ', '\t' };
    private bool StockTokens() {
        while (true) {
            string line = Reader.ReadLine();
            if (line == null) {
                return false;
            }

            string[] tokens = line.Split(_separator, StringSplitOptions.RemoveEmptyEntries);
            if (tokens.Length == 0) {
                continue;
            }

            foreach (string token in tokens) {
                TokenQueue.Enqueue(token);
            }

            return true;
        }
    }
}