LeetCode Remove Duplicates from Sorted Array

Description:

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.
Solution:

Sort the array, then skip the one whose value is the same as its former one.

import java.util.Arrays;

public class Solution {
public int removeDuplicates(int[] nums) {
if (nums.length == 0)
return 0;

Arrays.sort(nums);
int len = 1, key = 1;
int num = nums[0];

for (int i = 1; i < nums.length; i++) {
if (nums[i] != num) {
len++;
num = nums[i];
nums[key++] = nums[i];
}
}
return len;
}
}