def canPlaceFlowers(self, flowerbed, n):
return sum((len(zeros)  1) // 2 for zeros in ("0" + "".join(map(str, flowerbed)) + "0").split("1") if zeros != "") >= n
Key Observation
In the middle of the list, "000" can provide one available position, and "00000" can provide two, and so on. Therefore each zeros segment. can provide (len(zeros) 1 ) // 2 positions.
Corner Cases

For the zeros in the list edge, it only takes "00" to provide a position. However, we can align the rule by padding "0" in both ends of the list.

We have to exclude the case that zeros == "", that happens at splitting two adjacent ones "11", since (0 1) // 2 = 1 violate the general rule.