leetcode: 80. Remove Duplicates from Sorted Array II

# Follow up for "Remove Duplicates":
# What if duplicates are allowed at most twice?
#
# For example,
# Given sorted array nums = [1,1,1,2,2,3],
#
# Your function should return length = 5, 
# with the first five elements of nums being 1, 1, 2, 2 and 3.
# It doesn't matter what you leave beyond the new length.

class Solution():
    def removeDuplicates(self, x):
        if len(x) < 2:
            return len(x)
        cur = 2
        for _ in range(2, len(x)):
            if x[cur] == x[cur-2]:
                del x[cur]
            else:
                cur += 1
        return cur


if __name__ == "__main__":
    assert Solution().removeDuplicates([1, 1, 1, 2, 2, 3]) == 5