0050-powx-n.rb

# frozen_string_literal: true

# 50. Pow(x, n)
# https://leetcode.com/problems/powx-n
# Medium

=begin
Implement pow(x, n), which calculates x raised to the power n (i.e., x**n).

Example 1:
Input: x = 2.00000, n = 10
Output: 1024.00000

Example 2:
Input: x = 2.10000, n = 3
Output: 9.26100

Example 3:
Input: x = 2.00000, n = -2
Output: 0.25000
Explanation: 2-2 = 1/22 = 1/4 = 0.25

Constraints:
-100.0 < x < 100.0
-231 <= n <= 231-1
n is an integer.
Either x is not zero or n > 0.
-104 <= xn <= 104
=end

# @param {Float} x
# @param {Integer} n
# @return {Float}
defpow(x,n)
return1ifn.zero?
return(1 / pow(x, -n))ifn.negative?
returnx * pow(x,n - 1)ifn.odd?
pow(x * x,n / 2)
end

defmy_pow(x,n)
pow(x,n).round(5)
end

# **************** #
# TEST #
# **************** #

require"test/unit"
classTest_my_pow < Test::Unit::TestCase
deftest_
assert_equal1024.00000,my_pow(2.00000,10)
assert_equal9.26100,my_pow(2.10000,3)
assert_equal0.25000,my_pow(2.00000, -2)
end
end