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Remove Duplicates from Sorted Array

Certification: Basic Level Accuracy: 68.18% Submissions: 22 Points: 5

Write a Java program to remove duplicates from a sorted array. Given a sorted array nums, remove the duplicates in-place such that each element appears only once and returns the new length.

Example 1
    

  • Input: nums = [1,1,2]
    • 

  • Output: 2, nums = [1,2,...]
    • 

  • Explanation:

      

    • Only one duplicate removed, array becomes [1,2]
      • 

    

    •
Example 2
    

  • Input: nums = [0,0,1,1,1,2,2,3,3,4]
    • 

  • Output: 5, nums = [0,1,2,3,4,...]
    • 

  • Explanation:

      

    • All duplicates are removed in-place
      • 

    

    •
Constraints
    

  • 0 ≤ nums.length ≤ 3 * 10^4
    • 

  • -10^4 ≤ nums[i] ≤ 10^4
    • 

  • nums is sorted in non-decreasing order
    • 

  • Time Complexity: O(n)
    • 

  • Space Complexity: O(1)
    •
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Hint
Solution

Solution Hints

    
  
  • Use two pointers: one for the current position and one for the non-duplicate array
    • 
  
  • Compare adjacent elements to find duplicates
    • 
  
  • Move unique elements to the front of the array
    • 
  
  • Keep track of the length of the array with non-duplicates
    • 
  
  • Return the new length of the array
    •

Steps to solve by this approach:

 Step 1: Handle the edge case - if the array is empty, return 0.
 Step 2: Initialize a pointer i at index 0, which will track the position where the next unique element should be placed.
 Step 3: Iterate through the array starting from index 1 with another pointer j.
 Step 4: If the current element at index j is different from the element at index i, increment i and copy the element at j to position i.
 Step 5: Continue this process until the end of the array is reached.
 Step 6: Return i+1, which represents the length of the array with unique elements.
 Step 7: The first i+1 elements of the array now contain all the unique elements in the same order they appeared.

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