521. 去除重复元素

class Solution:
    """
    @param nums: an array of integers
    @return: the number of unique integers
    """
    def deduplication(self, nums):
        # write your code here
        #双指针写法，一个记录，一个走,如果相等，则替换
        length, count = len(nums), 0 
        left, right = 0,length - 1
        dict = {}

        #定义主指针
        while left <= right:
            if nums[left] in dict:
                nums[left], nums[right] = nums[right], nums[left]
                right -= 1
            else:
                dict[nums[left]] = True
                count += 1
                left += 1 

        return  count