26.remove-duplicates-from-sorted-array.python3.py

#
# [26] Remove Duplicates from Sorted Array
#
# https://leetcode.com/problems/remove-duplicates-from-sorted-array/description/
#
# algorithms
# Easy (37.69%)
# Total Accepted:    417K
# Total Submissions: 1.1M
# Testcase Example:  '[1,1,2]'
#
# Given a sorted array nums, remove the duplicates in-place such that each
# element appear only once and return the new length.
#
# Do not allocate extra space for another array, you must do this by modifying
# the input array in-place with O(1) extra memory.
#
# Example 1:
#
#
# Given nums = [1,1,2],
#
# Your function should return length = 2, with the first two elements of nums
# being 1 and 2 respectively.
#
# It doesn't matter what you leave beyond the returned length.
#
# Example 2:
#
#
# Given nums = [0,0,1,1,1,2,2,3,3,4],
#
# Your function should return length = 5, with the first five elements of nums
# being modified to 0, 1, 2, 3, and 4 respectively.
#
# It doesn't matter what values are set beyond the returned length.
#
#
# Clarification:
#
# Confused why the returned value is an integer but your answer is an array?
#
# Note that the input array is passed in by reference, which means modification
# to the input array will be known to the caller as well.
#
# Internally you can think of this:
#
#
# // nums is passed in by reference. (i.e., without making a copy)
# int len = removeDuplicates(nums);
#
# // any modification to nums in your function would be known by the caller.
# // using the length returned by your function, it prints the first len
# elements.
# for (int i = 0; i < len; i++) {
# print(nums[i]);
# }
#
#


class Solution:
    def removeDuplicates(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        if len(nums) < 2:
            return len(nums)

        length = len(nums)
        swap_index, cur = 0, 0
        while cur < length:
            # deal with one number with all its dups
            while cur < length-1 and nums[cur] == nums[cur+1]:
                cur += 1
            self.swap(nums, swap_index, cur)
            swap_index += 1
            cur += 1

        return swap_index

    def swap(self, nums, i1, i2):
        nums[i1], nums[i2] = nums[i2], nums[i1]


# if __name__ == "__main__":
#     nums = [[1, 1, 2, 2, 3, 3, 3, 4],
#             [1, 2, 2, 3],
#             ]
#     ex = Solution()
#     for num in nums:
#         print(num)
#         print(ex.removeDuplicates(num))
#         print(num)
#