Welcome to collectivesolver - Programming & Software Q&A with code examples. A website with trusted programming answers. All programs are tested and work.

Contact: aviboots(AT)netvision.net.il

Semrush - keyword research tool

Turn ChatGPT, Claude, Gemini, And CoPilot Into Your Personal Assistant, Business Coach, Content Creator, And More

AFFILIATE MARKETING Your all-in-one performance engine Manage affiliates, creators, and customer referrals in one unified platform—turning every partnership into measurable growth
Secure & Reliable Web Hosting, Free Domain, Free SSL, 1-Click WordPress Install, Expert 24/7 Support

Boost your online presence with premium web hosting and servers

Disclosure: My content contains affiliate links.

42,844 questions

55,671 answers

573 users

How to traverse an array from both sides at the same time in JavaScript

1 Answer

0 votes
/*
    Demonstration of traversing an array from both ends at the same time
    in idiomatic JavaScript.

    We use the classic "two‑index" technique:
        - left  starts at index 0
        - right starts at index array.length - 1
    Both move toward the center.

    This approach is efficient (O(n)), simple, and widely used in
    algorithms such as palindrome checks, partitioning, and pair searching.
*/

// ------------------------------------------------------------
// Function: traverseFromBothSides
// Purpose:  Traverse an array from both ends simultaneously.
// ------------------------------------------------------------
function traverseFromBothSides(arr) {
    let left = 0;
    let right = arr.length - 1;

    // Move inward until the indices cross
    while (left <= right) {
        console.log(`Left: ${arr[left]}, Right: ${arr[right]}`);
        left++;
        right--;
    }
}

// ------------------------------------------------------------
// Main program
// ------------------------------------------------------------
const array = [10, 20, 30, 40, 50, 60, 70, 80, 90];

console.log("Traversing from both sides:");
traverseFromBothSides(array);


/*
run:

Traversing from both sides:
Left: 10, Right: 90
Left: 20, Right: 80
Left: 30, Right: 70
Left: 40, Right: 60
Left: 50, Right: 50

*/

 



answered Jul 31 by avibootz
...