Short Problem Definition:
Cover “Manhattan skyline” using the minimum number of rectangles.
expected worst-case time complexity is O(N);
expected worst-case space complexity is O(N)
The explanation to this challenge has been posted on the Codility web, you can read it here.
def solution(H): block_cnt = 0 stack =  for height in H: # remove all blocks that are bigger than my height while len(stack) != 0 and stack[-1] &gt; height: stack.pop() if len(stack) != 0 and stack[-1] == height: # we already paid for this size pass else: # new block is required, push it's size to the stack block_cnt += 1 stack.append(height) return block_cnt
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