[LeetCode] 26. Remove Duplicates from Sorted Array

Problem : https://leetcode.com/problems/remove-duplicates-from-sorted-array/

Use 2 pointers to traverse the sorted array. p2 moves forward 1 number each time. p1 moves forward only when find unique number.

Time Complexity :  O ( len(nums) )

Space Complexity:  O ( 1 ),   remove duplicated number in space.

class Solution(object):
    def removeDuplicates(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        
        if not nums:
            return 0
        
        p1, p2 = 1, 1
        last = nums[0]
        
        while p2 < len(nums):
            if nums[p2] != last:
                nums[p1] = nums[p2]
                last = nums[p2]
                p1 += 1
            
            p2 += 1
        
        return p1