Solution.java

/**
 * 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.
 */

public class Solution {
    public int removeDuplicates(int[] nums) {
        if (nums == null || nums.length <= 0) {
            return 0;
        } else if (nums.length <= 1) {
            return 1;
        }
        int curr = 0;
        int runner = 1;
        while (runner < nums.length) {
            if (nums[runner] != nums[curr]) {
                curr++;
                nums[curr] = nums[runner];
            }
            runner++;
        }
        
        return curr+1;
    }
}