724. Find Pivot Index | Explained in 3 Approaches | LeetCode Java Solution

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Timelines:
0:00 Intro
03:50 Approach 1
08:40 Approach 2
14:00 Approach 3
22:01 Coding at LeetCode Platform

Welcome to our LeetCode DSA series! In this video, we tackle problem 724. Find Pivot Index and break down three effective methods to solve it:

Brute Force Approach: We start with a basic brute force method to locate the pivot index by checking each position in the array to find a point where the sum of elements to the left equals the sum on the right. This method provides insight into the problem but can be optimized for performance.

Left Sum and Right Sum Arrays: In this approach, we introduce left and right sum arrays to pre-calculate the cumulative sum of elements from each side. This helps avoid repetitive sum calculations, making the solution more efficient.

Optimized Single-Pass Solution: Finally, we present an efficient Java solution that finds the pivot index in a single pass through the array. Here, we keep track of cumulative sums on both sides as we iterate, reducing the need for extra space and improving the solution’s performance.

Key Points Covered:
Brute Force Solution: O(n²) complexity due to repeated sums.
Prefix Sum Array: Utilizing extra arrays to optimize and reduce repeated calculations.
Optimal Single-Pass Solution: An O(n) approach using minimal space, perfect for large inputs.

Whether you're just starting with DSA or preparing for coding interviews, this video will guide you through various methods to tackle array problems efficiently. Don’t forget to check out our full LeetCode DSA series here for more problem-solving insights!

Whether you're prepping for coding interviews or improving problem-solving skills, understanding array manipulation techniques like these can be crucial.

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