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: from bisect import *
  
  n, k = map(int, input().split())
  candles = list(map(int, input().split()))
  i0 = bisect_right(candles, 0)
  MIN = float("inf")
  if i0 - k >= 0:
      MIN = -candles[i0 - k]
  i_start = max(0, i0 - k + 1)
  if 0 in candles:
      i0 -= 1
  if i0 + k - 1 <= n - 1:
      MIN = min(MIN, candles[i0 + k - 1])
  i_end = min(i0, n - k + 1)
  for i in range(i_start, i_end):
      L = -candles[i]
      R = candles[i + k - 1]
      temp = L + R + min(L, R)
      if temp < MIN:
          MIN = temp
  print(MIN)
  
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"}]