第 n 个异或斐波那契数

原文:https://www.geeksforgeeks.org/nth-xor-fibonacci-number/

给定三个整数 abN ,其中 ab 是异或斐波那契数列的前两个项,任务是找到 N 项。 异或斐波那契数列的第 n 项定义为f(n)= f(n–1)^ f(n–2),其中 ^ 是按位异或。 例:

输入: a = 1,b = 2,N = 5 输出:3 f(0)= 1 f(1)= 2 f(2)= 1 ^ 2 = 3 f(3)= 2 ^ 3 = 1 f(4)= 1 ^ 3 = 2 f(5)= 1 ^ 2 = 3 输入: a = 5,b = 11,n

进场:自, a ^ a = 0 并给出

F(0) =

可以观察到,答案在每 3 个数字后重复一次。所以答案是 F(N % 3) 其中 F(0) = a,F(1) = b 和 F(2) = a ^ b 。 以下是上述方法的实现:

C++

// C++ implementation of the approach
#include <bits/stdc++.h>
using namespace std;

// Function to return the nth XOR Fibonacci number
int nthXorFib(int n, int a, int b)
{
    if (n == 0)
        return a;
    if (n == 1)
        return b;
    if (n == 2)
        return (a ^ b);

    return nthXorFib(n % 3, a, b);
}

// Driver code
int main()
{
    int a = 1, b = 2, n = 10;

    cout << nthXorFib(n, a, b);

    return 0;
}

Java 语言(一种计算机语言,尤用于创建网站)

// Java implementation of the above approach
class GFG
{

    // Function to return the
    // nth XOR Fibonacci number
    static int nthXorFib(int n, int a, int b)
    {
        if (n == 0)
            return a;
        if (n == 1)
            return b;
        if (n == 2)
            return (a ^ b);

        return nthXorFib(n % 3, a, b);
    }

    // Driver code
    public static void main (String[] args)
    {
        int a = 1, b = 2, n = 10;

        System.out.println(nthXorFib(n, a, b));
    }
}

// This code is contributed by AnkitRai01

Python 3

# Python3 implementation of the approach

# Function to return
# the nth XOR Fibonacci number
def nthXorFib(n, a, b):
    if n == 0 :
        return a
    if n == 1 :
        return b
    if n == 2 :
        return a ^ b

    return nthXorFib(n % 3, a, b)

# Driver code
a = 1
b = 2
n = 10
print(nthXorFib(n, a, b))

# This code is contributed by divyamohan123

C

// C# implementation of the above approach
using System;

class GFG
{

    // Function to return the
    // nth XOR Fibonacci number
    static int nthXorFib(int n, int a, int b)
    {
        if (n == 0)
            return a;
        if (n == 1)
            return b;
        if (n == 2)
            return (a ^ b);

        return nthXorFib(n % 3, a, b);
    }

    // Driver code
    public static void Main (String[] args)
    {
        int a = 1, b = 2, n = 10;

        Console.WriteLine(nthXorFib(n, a, b));
    }
}

// This code is contributed by Princi Singh

java 描述语言

<script>

// Javascript implementation of the approach

// Function to return the nth XOR Fibonacci number
function nthXorFib(n, a, b)
{
    if (n == 0)
        return a;
    if (n == 1)
        return b;
    if (n == 2)
        return (a ^ b);

    return nthXorFib(n % 3, a, b);
}

// Driver code
    let a = 1, b = 2, n = 10;

    document.write(nthXorFib(n, a, b));

</script>

Output: 

2

时间复杂度: O(1)