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Remove Duplicates

Certification: Advanced Level Accuracy: 0% Submissions: 0 Points: 8

Write a C# program to remove duplicates from a sorted array in-place. Return the length of the array after removing duplicates. Do not allocate extra space for another array.

Example 1
    
  
  • Input: nums = [1, 1, 2]
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  • Output: 2, nums = [1, 2, ...]
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  • Explanation: 
    
      
      
    • The first two elements of nums are 1 and 2 respectively.
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    • The function should return 2, the length of the array after removing duplicates.
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    • It doesn't matter what values are set beyond the returned length.
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    •
Example 2
    
  
  • Input: nums = [0, 0, 1, 1, 1, 2, 2, 3, 3, 4]
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  • Output: 5, nums = [0, 1, 2, 3, 4, ...]
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  • Explanation: 
    
      
      
    • The first five elements of nums should be 0, 1, 2, 3, and 4 respectively.
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    • The function should return 5, and it doesn't matter what values are set beyond the returned length.
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Constraints
    
  
  • 0 ≤ nums.length ≤ 3 * 10^4
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  • -10^4 ≤ nums[i] ≤ 10^4
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  • nums is sorted in non-decreasing order
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  • Time Complexity: O(n)
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  • Space Complexity: O(1)
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Hint
Solution

Solution Hints

    
  
  • Use the two-pointer technique
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  • Keep a pointer for the current position to place the next unique element
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  • Iterate through the array, comparing adjacent elements
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  • If a new unique element is found, place it at the position indicated by the first pointer
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  • Return the length of the resulting array
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Steps to solve by this approach:

 Step 1: Handle the edge case of an empty array.
 Step 2: Initialize a pointer (uniqueIndex) to keep track of the position for the next unique element.
 Step 3: Start from the second element (index 1) and compare it with the previous unique element.
 Step 4: If the current element is different from the element at uniqueIndex, increment uniqueIndex.
 Step 5: Assign the current element to the new uniqueIndex position.
 Step 6: Continue this process for all elements in the array.
 Step 7: Return uniqueIndex + 1, which represents the new length of the array without duplicates.

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