26_remove_duplicates_from_sorted_array.rb

#Leetcode Problem: https://leetcode.com/problems/remove-duplicates-from-sorted-array/
#Given a sorted array nums, remove the duplicates in-place such that each element appears only once and returns 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 a 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]);
# }
# ----------------------------------------------------------------------------------------------------------------------
# @param {Integer[]} nums
# @return {Integer}
def remove_duplicates(nums)
  index = 1
  nums.length.times do |i|
    if nums[i] != nums[i + 1]
      nums[index] = nums[i + 1]
      index += 1
    end
  end
  index
end

p remove_duplicates [1, 1, 2]

p remove_duplicates [0, 0, 1, 1, 1, 2, 2, 3, 3, 4]