Remove Duplicates from Sorted Array

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.

For 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.

解决这道题我们用两个指针，一个指针用于遍历数组，另外一个用于指向不重复的元素。实现代码如下：

public class Solution {
    public int removeDuplicates(int[] nums) {
        if(nums == null || nums.length == 0) return 0;
        int index = 1;
        for(int i = 1; i < nums.length; i++) {
            if(nums[i] != nums[i - 1])
            nums[index ++] = nums[i];
        }
        return index;
    }
}