package main

// in-place
func removeDuplicates(nums []int) int {
	if len(nums) == 0 {
		return 0
	}
	// index of the last element in array
	last := 0
	for curr := 1; curr < len(nums); curr++ {
		if nums[curr] != nums[last] {
			nums[last+1] = nums[curr]
			last++
		}
	}
	// size = last_index + 1
	return last + 1
}