# Problem

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.

# Java 实现

``````
package com.coderli.leetcode.algorithms.easy;

/**
* Given a sorted array, remove the duplicates in place such that each element appear only once and
* return the new length.
* <p>
* Do not allocate extra space for another array, you must do this in place with constant memory.
* <p>
* For example,
* Given input array nums = [1,1,2],
* <p>
* 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.
*
* @author li.hzh 2017-10-22 21:24
*/
public class RemoveDuplicatesFromSortedArray {

public static void main(String[] args) {
RemoveDuplicatesFromSortedArray rdfSortedArray = new RemoveDuplicatesFromSortedArray();
System.out.println(rdfSortedArray.removeDuplicates(new int[]{1}));
System.out.println(rdfSortedArray.removeDuplicates(new int[]{1, 1}));
System.out.println(rdfSortedArray.removeDuplicates(new int[]{1, 1, 2}));
System.out.println(rdfSortedArray.removeDuplicates(new int[]{1, 1, 2, 2}));
System.out.println(rdfSortedArray.removeDuplicates(new int[]{1, 1, 1, 2, 2}));
System.out.println(rdfSortedArray.removeDuplicates(new int[]{1, 1, 2, 2, 3, 3}));
System.out.println(rdfSortedArray.removeDuplicates(new int[]{1, 2, 2, 3, 4, 4}));
}

public int removeDuplicates(int[] nums) {
if (nums == null || nums.length == 0) {
return 0;
}
int compareValue = nums[0];
int result = 1;
for (int i = 1; i < nums.length; i++) {
if (compareValue < nums[i]){
compareValue = nums[i];
nums[result] = compareValue;
result++;
}
}
return result;
}

}

``````

Thanks a lot.