Maximising Efficiency: Harnessing the Two-Pointer Technique

Two-Pointer Technique is a problem-solving approach that employs two pointers to traverse data structures such as arrays or linked lists. It is a search algorithm which is used by comparing elements pointed by two pointers. These pointers can start at same or different positions by corresponding to index, move towards each other or in opposite directions and then be updated accordingly to help find specific solutions to the given problem.

When to Use the Two-Pointer Technique?

The 2-Pointer technique is particularly useful in scenarios where you need to find pairs, triplets, or subsequences that satisfy certain conditions. Here are some situations where the 2-Pointer technique shines:

1. Finding Pairs with Specific Sum
2. Remove elements in-place
3. Remove Duplicates from Sorted Array
4. (Will be updated when I find more examples…)

Tips

Two-Pointer technique is most effective when the data structure is sorted or has some inherent order.

What to think about when you find Two-Pointer Technique may solve the issue?

1. How many pointers do you need?
2. What’s the functionality for each pointer?
3. Where do you put your pointers?
4. Which direction does each pointer move towards?
5. When should the pointer move? in what condition?
6. When will the pointer stop?

Conclusion

Two-pointer Technique is powerful. Its effectiveness in handling ordered data structures, combined with improved time&space complexity, makes it a valuable addition to your problem-solving toolkit.