Most Important Two Pointer Problems for Google Coding Interviews
Two Pointers is one of the most powerful techniques used in Google coding interviews. It helps optimize brute-force solutions into efficient linear-time algorithms, especially for array and string problems.
In this article, you'll find the most frequently asked Two Pointers LeetCode questions in Google interviews, along with their difficulty level and frequency.
| Sl.No | Question | Difficulty | Frequency | LeetCode Link |
|---|
| 1 | Trapping Rain Water | HARD | 85.90% | Solve |
| 2 | Merge Sorted Array | EASY | 81.40% | Solve |
| 3 | Longest Palindromic Substring | MEDIUM | 77.10% | Solve |
| 4 | 3Sum | MEDIUM | 76.70% | Solve |
| 5 | Container With Most Water | MEDIUM | 75.10% | Solve |
| 6 | Merge Strings Alternately | EASY | 75.00% | Solve |
| 7 | Next Permutation | MEDIUM | 63.20% | Solve |
| 8 | Remove Duplicates from Sorted Array | EASY | 62.90% | Solve |
| 9 | Reverse Words in a String | MEDIUM | 59.50% | Solve |
| 10 | Valid Palindrome | EASY | 59.30% | Solve |
| 11 | 4Sum | MEDIUM | 57.60% | Solve |
| 12 | Sort Colors | MEDIUM | 56.40% | Solve |
| 13 | Find Median from Data Stream | HARD | 55.40% | Solve |
| 14 | Remove Nth Node From End of List | MEDIUM | 54.80% | Solve |
| 15 | Find the Index of the First Occurrence in a String | EASY | 52.80% | Solve |
| 16 | Remove Element | EASY | 52.80% | Solve |
| 17 | Move Pieces to Obtain a String | MEDIUM | 50.00% | Solve |
| 18 | Remove Duplicates from Sorted Array II | MEDIUM | 44.30% | Solve |
| 19 | Rotate List | MEDIUM | 43.80% | Solve |
| 20 | Find the Duplicate Number | MEDIUM | 43.10% | Solve |
| 21 | 3Sum Closest | MEDIUM | 42.70% | Solve |
| 22 | Expressive Words | MEDIUM | 39.80% | Solve |
| 23 | Valid Word Abbreviation | EASY | 37.50% | Solve |
| 24 | Two Sum II - Input Array Is Sorted | MEDIUM | 37.50% | Solve |
| 25 | Check If N and Its Double Exist | EASY | 37.50% | Solve |
| 26 | Partition List | MEDIUM | 35.30% | Solve |
| 27 | Linked List Cycle | EASY | 35.20% | Solve |
| 28 | 3Sum Smaller | MEDIUM | 27.50% | Solve |
| 29 | Strobogrammatic Number | EASY | 25.10% | Solve |
| 30 | Range Sum of Sorted Subarray Sums | MEDIUM | 25.00% | Solve |
| 31 | Sort Transformed Array | MEDIUM | 25.00% | Solve |
| 32 | Number of Subsequences That Satisfy the Given Sum Condition | MEDIUM | 25.00% | Solve |
| 33 | Find All K-Distant Indices in an Array | EASY | 25.00% | Solve |
| 34 | Sentence Similarity III | MEDIUM | 25.00% | Solve |
| 35 | Count the Number of Fair Pairs | MEDIUM | 25.00% | Solve |
| 36 | Magical String | MEDIUM | 25.00% | Solve |
| 37 | Maximum Score of a Good Subarray | HARD | 25.00% | Solve |
| 38 | Longest Word in Dictionary through Deleting | MEDIUM | 25.00% | Solve |
| 39 | Bag of Tokens | MEDIUM | 25.00% | Solve |
| 40 | Longest Chunked Palindrome Decomposition | HARD | 25.00% | Solve |
| 41 | Merge Two 2D Arrays by Summing Values | EASY | 25.00% | Solve |
| 42 | The k Strongest Values in an Array | MEDIUM | 25.00% | Solve |
| 43 | Watering Plants II | MEDIUM | 25.00% | Solve |
| 44 | Minimum Adjacent Swaps to Reach the Kth Smallest Number | MEDIUM | 25.00% | Solve |
| 45 | Sum of Square Numbers | MEDIUM | 25.00% | Solve |
| 46 | Push Dominoes | MEDIUM | 25.00% | Solve |
| 47 | Closest Binary Search Tree Value II | HARD | 23.80% | Solve |
| 48 | Flatten 2D Vector | MEDIUM | 23.80% | Solve |
| 49 | Remove Duplicates from Sorted List II | MEDIUM | 22.10% | Solve |
| 50 | Max Number of K-Sum Pairs | MEDIUM | 12.50% | Solve |
Why Two Pointers is Important for Google Interviews
Google often tests your ability to:
- Optimize solutions (O(n²) → O(n))
- Handle sorted arrays efficiently
- Solve substring and subarray problems
- Use space-efficient approaches
If you master Two Pointers, you automatically improve in:
- Arrays
- Strings
- Sliding Window problems
Related:
Common Patterns to Master
To crack Google interviews, focus on these Two Pointer patterns:
- Opposite Direction Pointers (start + end)
- Fast & Slow Pointers (cycle detection)
- Sliding Window Optimization
- Partitioning & Pair Matching
- Removing duplicates in-place
How to Prepare Effectively
Follow this strategy:
- Start with easy problems (2–3 questions)
- Move to medium-level interview questions
- Time yourself (important for Google rounds)
- Track your progress consistently
Use our tracker tool to stay consistent:
Google LeetCode Interview Questions Tracker
Complete Google Interview Preparation
Once you're done with Two Pointers, move to these must-do topics:
Explore All Google Questions (High Priority)
If you're serious about cracking Google:
Google LeetCode Questions (247+ Problems with Frequency)
Company-wise Preparation
You can also explore questions asked in other top companies:
Final Thoughts
Two Pointers is not just a topic it's a shortcut to solving problems faster in interviews.
If you practice these questions consistently and understand patterns deeply, you’ll be ahead of most candidates.
Pro Tip: Combine Two Pointers with Sliding Window + Hashing for maximum impact in Google interviews.
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