Pendulum

pendulum.go

package kata
import "sort"
// https://www.codewars.com/kata/the-poet-and-the-pendulum/train/go
func Pendulum(values []int) []int {
   srt := append([]int{},values...)
   answer := make([]int,0,0)
   sort.Ints(srt)
   for key, value := range srt {
     if 0 == key%2 {
       answer = append([]int{value}, answer...)
     }else{
       answer = append(answer, value)
     }
   }
   return answer
}

pendulum.js

// https://www.codewars.com/kata/the-poet-and-the-pendulum/train/javascript
function pendulum(values) {
    let sorted = [...values].sort((a,b) => a - b);
    let x = values.length % 2 ? parseInt(values.length/2) : parseInt((values.length - 1)/2);
    values[x] = sorted[0]
    for(var i=1, delta = i; i < sorted.length; i+=1){
      values[x + delta] = sorted[i]
      delta = delta > 0 ? -delta : -delta + 1
    }
    return values
}

pendulum.py

# https://www.codewars.com/kata/the-poet-and-the-pendulum/train/python
# Did not passed by time bounds
def pendulum(v):
    answer = []
    v.sort()
    for key, value in enumerate(v):
        answer.insert(0,value) if 0 == key%2 else answer.append(value) 
    return answer
    
# http://book.pythontips.com/en/latest/ternary_operators.html
# https://www.python-course.eu/python3_list_manipulation.php
# https://stackoverflow.com/a/34211482/8574922

# Passed
# https://www.codewars.com/kata/the-poet-and-the-pendulum/train/python
def pendulum(v):
    srt = v.copy()
    srt.sort()
    x = int(len(v)/2) if 1 == len(v)%2 else int((len(v) - 1)/2)
    v[x] = srt[0]
    i,delta = 1,1
    while i < len(v):
        v[x + delta] = srt[i]
        delta = -delta if delta > 0 else -delta + 1
        i += 1
    return v
    
# http://book.pythontips.com/en/latest/ternary_operators.html
# https://www.python-course.eu/python3_list_manipulation.php
# https://stackoverflow.com/a/34211482/8574922
        

pendulum.rb

# https://www.codewars.com/kata/the-poet-and-the-pendulum/train/ruby
def pendulum v
  l,r = [],[]
  v.sort.each_with_index do |value, index|
    index.even? ? l.push(value) : r.push(value)
  end
  l.reverse + r
end

# https://www.codewars.com/kata/the-poet-and-the-pendulum/train/ruby
# https://www.codewars.com/users/c0nspiracy
def pendulum v
  cycle = %i[unshift push].cycle
  v.sort.reduce([]) do |memo, value|
    memo.send(cycle.next, value)
  end
end

https://www.codewars.com/users/cave.on

https://www.codewars.com/users/FArekkusu

def pendulum(a):
    a = sorted(a)
    return a[::2][::-1] + a[1::2]