πŸš€ "The Secret Java Trick That Turns O(nΒ²) Into O(n)" – Two Pointer Technique EXPLAINED πŸ’‘

Mihir ChothaniMihir Chothani
2 min read

If you're learning Java and feel overwhelmed by DSA problems β€” there's one simple trick that can instantly boost your coding skills and impress interviewers...

It’s called the Two Pointer Technique, and it’s a total game-changer. πŸ‘‡


πŸ” What Is the Two Pointer Technique in Java?

The Two Pointer approach uses two indices to navigate an array:
➑ One starts from the left, the other from the right (or both from one side at different speeds).
➑ It’s a powerful pattern that replaces nested loops with a single O(n) pass.

Think of it like using two eyes instead of oneβ€”you suddenly see more, faster. 🧠


🧠 When Should You Use It?

This pattern solves some of the most common coding interview problems, like:

βœ… Finding pairs with a specific sum (e.g., sum == target)
βœ… Reversing an array in-place
βœ… Removing duplicates from a sorted array
βœ… Merging two sorted arrays
βœ… Solving many O(nΒ²) brute-force problems in just O(n)!


πŸ’₯ Why This Pattern Is a Game-Changer

🚫 No more nested loops
⚑ Cleaner code
πŸ’‘ Faster execution
πŸ”₯ Instant performance boost in many LeetCode-style problems


πŸ’‘ Real Example – Find Pair With Target Sum in Java

javaCopyEditint[] arr = {1, 2, 3, 4, 6};
int target = 6;
int left = 0, right = arr.length - 1;

while (left < right) {
    int sum = arr[left] + arr[right];
    if (sum == target) {
        System.out.println("Pair: " + arr[left] + ", " + arr[right]);
        break;
    } else if (sum < target) {
        left++;
    } else {
        right--;
    }
}

🟒 Output: Pair: 2, 4


❀️ Why You Should Master This in Java

Whether you're a DSA beginner, preparing for FAANG interviews, or just trying to write cleaner logic β€” mastering Two Pointer will 10x your thinking.

πŸ‘‰ Practice it.
πŸ‘‰ Use it.
πŸ‘‰ And let it become your secret weapon for cracking coding rounds like a pro.


πŸš€ Ready to take your Java game next level?

πŸ”– Save this.
πŸ“€ Share it with a coding buddy.
πŸ’¬ Comment your favorite Two Pointer problem below!


#JavaDSA #JavaDeveloper #DSA #TwoPointer #CrackTheCodingInterview #JavaTips #LearnInPublic #100DaysOfCode #CodeSmarter #HashnodeDev

1
Subscribe to my newsletter

Read articles from Mihir Chothani directly inside your inbox. Subscribe to the newsletter, and don't miss out.

Written by

Mihir Chothani
Mihir Chothani