output_description: Print the minimum time required to light K candles.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N K
      x_1 x_2 ... x_N
attempt: import math
  
  S = input().split(" ")
  N = int(S[0])
  K = int(S[1])
  
  arr = [int(s) for s in input().split(" ")]
  
  
  def calculate(n, k, arr):
      minsArr = []
      plusArr = []
      for ar in arr:
          if ar < 0:
              minsArr.append(ar)
          else:
              plusArr.append(ar)
  
      # find start index
      startIndex = -10000
  
      if len(minsArr) > k:
          startIndex = len(minsArr) - k
      else:
          startIndex = 0
  
      minValues = []
      while startIndex <= len(minsArr):
          tmpArr = arr[startIndex : startIndex + k]
          if len(tmpArr) < k:
              break
          minValue = 0
  
          if tmpArr[0] * tmpArr[-1] < 0:
              minValue = math.fabs(tmpArr[-1] - tmpArr[0]) + min(
                  math.fabs(tmpArr[-1]), math.fabs(tmpArr[0])
              )
          else:
              minValue = math.fabs(tmpArr[-1])
  
          minValues.append(minValue)
          startIndex = startIndex + 1
  
      return int(min(minValues))
  
  
  result = calculate(N, K, arr)
  print(result)
  
problem_description: Statement
  
  There are N candles placed on a number line. The i-th candle from the left is
  placed on coordinate x_i. Here, x_1 < x_2 < ... < x_N holds.
  
  Initially, no candles are burning. Snuke decides to light K of the N candles.
  
  Now, he is at coordinate 0. He can move left and right along the line with
  speed 1. He can also light a candle when he is at the same position as the
  candle, in negligible time.
  
  Find the minimum time required to light K candles.
samples: [{"input": "5 3\n    -30 -10 10 20 50", "output": "40\n    \n\nHe should move and light candles as follows:\n\n  * Move from coordinate 0 to -10.\n  * Light the second candle from the left.\n  * Move from coordinate -10 to 10.\n  * Light the third candle from the left.\n  * Move from coordinate 10 to 20.\n  * Light the fourth candle from the left.\n\n* * *"}, {"input": "3 2\n    10 20 30", "output": "20\n    \n\n* * *"}, {"input": "1 1\n    0", "output": "0\n    \n\n  * There may be a candle placed at coordinate 0.\n\n* * *"}, {"input": "8 5\n    -9 -7 -4 -3 1 2 3 4", "output": "10"}]