Leetcode 26 | Remove Duplicates from Sorted Array | Two Pointer O(N) | In-Place Trick
🔍 Problem Link : https://leetcode.com/problems/remove-dupli...
💻 GitHub Code : https://github.com/Shyam-jee/-TheDSACompiler
📺 Channel Link : / @thedsacompiler
🚀 Video Breakdown:
In this quick yet comprehensive tutorial, we solve Leetcode 26: Remove Duplicates from Sorted Array using the Two Pointer technique with O(N) time and O(1) space complexity. This is a fundamental array problem that appears in almost every coding interview and teaches essential in-place manipulation skills!
✨ What You’ll Master:
✅ Two Pointer Approach:
How the slow and fast pointer technique works
Why this is optimal for sorted arrays
The intuition behind in-place duplication removal
✅ In-Place Modification:
How to modify the input array without extra space
Returning the new length while maintaining original data structure
✅ Edge Cases Demystified:
Empty array (return 0)
Array with all duplicates (e.g., [1,1,1])
Array with no duplicates (e.g., [1,2,3])
Single element array (return 1)
✅ Visualization & Dry Runs:
Step-by-step process: [0,0,1,1,1,2,2,3,3,4] → New length = 5, Array = [0,1,2,3,4,_,_,_,_,_]
How the slow pointer tracks the last unique element
✅ Follow-Up Interview Questions:
What if the array is not sorted? (Use HashSet but O(N) space)
How to remove duplicates such that each element appears at most twice? (Leetcode 80)
What if we need to return the removed elements?
💡 Pro Tips for Viewers:
Pattern Recognition: This two-pointer technique is used in 26, 27, 80, 283—learn it once!
Interview Trick: Always clarify if you can modify the input array.
Pause and Try: Code the solution after the dry run!
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