Fibonacci.py

"""
Find the Nth number in Fibonacci sequence.

A Fibonacci sequence is defined as follow:

The first two numbers are 0 and 1.
The i th number is the sum of i-1 th number and i-2 th number.
The first ten numbers in Fibonacci sequence is:

0, 1, 1, 2, 3, 5, 8, 13, 21, 34 ...

Have you met this question in a real interview? Yes
Example
Given 1, return 0

Given 2, return 1

Given 10, return 34

Note
The Nth fibonacci number won't exceed the max value of signed 32-bit integer in the test cases.
"""
__author__ = 'Daniel'


class Solution:
    def fibonacci(self, n):
        """
        For loop in a functional way
        :param n: an integer
        :return: an integer f(n)
        """
        f = lambda n: reduce(lambda x, n: [x[1], x[0]+x[1]], range(n), [0, 1])[0]  # reduce(func, itr, accumulator)
        return f(n-1)