Remove Duplicate Numbers in Array

Given an array of integers, remove the duplicate numbers in it. 

You should:
1. Do it in place in the array.
2. Move the unique numbers to the front of the array.
3. Return the total number of the unique numbers.

 Notice

You don't need to keep the original order of the integers.

Have you met this question in a real interview? 

Yes

Example

Given nums = [1,3,1,4,4,2], you should:

1. Move duplicate integers to the tail of nums => nums = [1,3,4,2,?,?].
2. Return the number of unique integers in nums => 4.

Actually we don't care about what you place in ?, we only care about the part which has no duplicate integers.

一种非常常用的算法，需要非常短的时间内一次性的写出完整的代码

java

public class Solution {    /*     * @param nums: an array of integers     * @return: the number of unique integers     */    public int deduplication(int[] nums) {        // write your code here        if (nums == null || nums.length == 0) {            return 0;        }        Arrays.sort(nums);        int slow = 0;        int fast = 0;        while (fast < nums.length) {            if (nums[slow] != nums[fast]) {                nums[++slow] = nums[fast++];            } else{                fast++;            }        }        return slow + 1;    }}

python

class Solution:    """    @param: nums: an array of integers    @return: the number of unique integers    """    def deduplication(self, nums):        # write your code here        if nums is None or len(nums) == 0:            return 0        slow, fast = 0, 0        nums.sort()        while fast < len(nums):            if nums[slow] != nums[fast]:                slow += 1                nums[slow] = nums[fast]            fast += 1        return slow + 1