Remove Duplicates from Sorted Array
https://leetcode.com/problems/remove-duplicates-from-sorted-array/
func removeDuplicates(nums []int) int {
i := 0
j := 1
for ; j < len(nums); j++ {
if nums[j] == nums[j-1] {
// duplicate
continue
}
nums[i+1] = nums[j]
i++
}
return i+1
}