Two Pointer Technique
Master the elegant technique that uses two reference points to process data with O(n) efficiency instead of the brute force O(nĀ²) approach.
šThe Library Hunt
Imagine searching for a specific book in a massive library with millions of volumes. You could start from one end and check each book one by one ā a process that might take days!
The Aha Moment
What if you had a friend? You start from one end, they start from the other, and you move toward each other. When you find books with lower catalog numbers than your target, you move forward. When your friend finds books with higher numbers, they move backward.
This collaborative search will find your book in half the time! This simple approach mirrors exactly how the two-pointer technique works in algorithms ā approaching a problem from two directions simultaneously is far more efficient than the brute force alternative.
The lesson
"Sometimes, approaching a problem from two directions simultaneously is more efficient than tackling it from a single starting point."
š®Interactive Visualization
See the two-pointer technique in action: finding a pair of numbers that add up to 9 in the array [2, 7, 11, 15].
Time Complexity
Space Complexity
When to use this pattern:
- āFinding pairs in sorted arrays
- āChecking if strings are palindromes
- āContainer with most water problem