No26.remove-duplicates-from-sorted-array.swift

/*
 * Difficulty:
 * Easy
 *
 * Desc:
 * Given a sorted array, 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 in place with constant memory.
 *
 * Example:
 * Given input array 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 new length.
 *
 * 去除一个已排序的数组中重复的元素，且不能占用额外的空间（不能新建）
 */

class Solution {
    func removeDuplicates(_ nums: inout [Int]) -> Int {
        var index = 0
        while index < nums.count {
            if index > 0 && nums[index] == nums[index - 1] {
                nums.remove(at: index)
            } else {
                index += 1
            }
        }
        return nums.count
    }
}