netskope2_repeating_chars.py

from collection import deque

def minWindow3(source, match):
  counts = {}
  for c in match:
    counts[c] = counts[c] + 1 if c in counts else 1
  
  lastIndexSeen = {c: deque(maxsize=counts[c]) for c in counts}
  minLength = float("inf")
  accMaxIndex = None
  accMinIndex = None
  for i, c in enumerate(lastIndexSeen):
  	if c in lastIndexSeen:
  		lastIndexSeen[c].append(i)
  	maxIndex = lastIndexSeen[max(lastIndexSeen, lambda key: viewTop(lastIndexSeen[c]))]
  	minIndex = lastIndexSeen[min(lastIndexSeen, lambda key: viewEnd(lastIndexSeen[c]))]
  	length = maxIndex + 1 - maxIndex
  	if length < minLength:
  		minLength = length
  		accMaxIndex = maxIndex
  		accMinIndex = minIndex
  return source[accMinIndex:accMaxIndex + 1]




 def viewTop(queue):
 	value = queue.popright()
 	queue.append(value)
 	return value

 def viewEnd(queue):
 	value = queue.pop()
 	queue.appendleft(value)
 	return value