Submission #1034920


Source Code Expand

using System;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Collections.Generic;
using System.Diagnostics;
using System.Numerics;
using Enu = System.Linq.Enumerable;

public class Program
{
    static readonly int Mod = (int)1e9 + 7;

    public void Solve()
    {
        int N = Reader.Int(), X = Reader.Int();
        var C = new long[N + 1];
        var Y = new long[N + 1];
        for (int i = 1; i <= N; i++) C[i] = Y[i] = 1;
        var ans = LinearRecurrenceRelation.Calc(C, Y, X, Mod);
        Console.WriteLine(ans);
        Console.ReadLine();
    }
}

class LinearRecurrenceRelation
{
    // F(n + 1) = C[0] + C[1] * Y(1) + C[2] * Y(2) + ... + C[n] * Y(n)
    // return F(x)
    public static long Calc(long[] C, long[] Y, long x, long mod)
    {
        if (x < Y.Length) return Y[x];
        int N = C.Length;
        C = Power(C, x, mod);
        long res = 0;
        for (int i = 0; i < C.Length; i++)
            res = (res + C[i] * Y[i]) % mod;
        return res;
    }
    static long[] Power(long[] A, long p, long mod)
    {
        long[] x = new long[A.Length], res = new long[A.Length];
        x[1] = res[0] = 1;
        for (; p > 0; p >>= 1, x = Mult(x, x, A, mod))
            if (p % 2 == 1) res = Mult(res, x, A, mod);
        return res;
    }
    static long[] Mult(long[] A, long[] B, long[] C, long mod)
    {
        var res = new long[A.Length * 2];
        for (int ai = 0; ai < A.Length; ai++)
            for (int bi = 0; bi < B.Length; bi++)
            {
                res[ai + bi] += A[ai] * B[bi];
                res[ai + bi] %= mod;
            }
        for (int x = res.Length - 1; x >= A.Length; x--)
            for (int y = 0; y < C.Length; y++)
            {
                res[x - y - 1] += C[C.Length - y - 1] * res[x];
                res[x - y - 1] %= mod;
            }
        var r = new long[A.Length];
        Array.Copy(res, r, r.Length);
        return r;
    }
}


class Entry { static void Main() { new Program().Solve(); } }
class Reader
{
    static TextReader reader = Console.In;
    static readonly char[] separator = { ' ' };
    static readonly StringSplitOptions op = StringSplitOptions.RemoveEmptyEntries;
    static string[] A = new string[0];
    static int i;
    static void Init() { A = new string[0]; }
    public static void Set(TextReader r) { reader = r; Init(); }
    public static void Set(string file) { reader = new StreamReader(file); Init(); }
    public static bool HasNext() { return CheckNext(); }
    public static string String() { return Next(); }
    public static int Int() { return int.Parse(Next()); }
    public static long Long() { return long.Parse(Next()); }
    public static double Double() { return double.Parse(Next()); }
    public static int[] IntLine() { return Array.ConvertAll(Split(Line()), int.Parse); }
    public static int[] IntArray(int N) { return Range(N, Int); }
    public static int[][] IntTable(int H) { return Range(H, IntLine); }
    public static string[] StringArray(int N) { return Range(N, Next); }
    public static string[][] StringTable(int N) { return Range(N, () => Split(Line())); }
    public static string Line() { return reader.ReadLine().Trim(); }
    public static T[] Range<T>(int N, Func<T> f) { var r = new T[N]; for (int i = 0; i < N; r[i++] = f()) ; return r; }
    static string[] Split(string s) { return s.Split(separator, op); }
    static string Next() { CheckNext(); return A[i++]; }
    static bool CheckNext()
    {
        if (i < A.Length) return true;
        string line = reader.ReadLine();
        if (line == null) return false;
        if (line == "") return CheckNext();
        A = Split(line);
        i = 0;
        return true;
    }
}

Submission Info

Submission Time
Task T - フィボナッチ
User eitaho
Language C# (Mono 2.10.8.1)
Score 8
Code Size 3872 Byte
Status AC
Exec Time 1304 ms
Memory 2968 KB

Judge Result

Set Name All
Score / Max Score 8 / 8
Status
AC × 7
Set Name Test Cases
All 00, 01, 02, 03, 04, 90, 91
Case Name Status Exec Time Memory
00 AC 1200 ms 2928 KB
01 AC 769 ms 2952 KB
02 AC 1304 ms 2888 KB
03 AC 255 ms 2968 KB
04 AC 47 ms 2696 KB
90 AC 49 ms 2684 KB
91 AC 49 ms 2728 KB