LeetCode 238: Product of Array Except Self Solution

Master LeetCode problem 238 (Product of Array Except Self), a medium challenge, with our optimized solutions in Java, C++, and Python. Explore detailed explanations, test your code in our interactive editor, and prepare for coding interviews.

238. Product of Array Except Self

Medium

Array Prefix Sum

Problem Explanation

Explanation

To solve this problem, we can calculate the product of all elements to the left of each element and the product of all elements to the right of each element separately. Then, we can multiply these two products together to get the final product excluding the current element. This approach avoids using division and runs in O(n) time complexity.

Initialize two arrays leftProducts and rightProducts of the same size as the input array nums.
Calculate the product of all elements to the left of each element in nums and store it in leftProducts.
Calculate the product of all elements to the right of each element in nums and store it in rightProducts.
Multiply the corresponding elements in leftProducts and rightProducts to get the final result.

Solution Code

class Solution {
    public int[] productExceptSelf(int[] nums) {
        int n = nums.length;
        int[] result = new int[n];
        
        int[] leftProducts = new int[n];
        int[] rightProducts = new int[n];
        
        leftProducts[0] = 1;
        for (int i = 1; i < n; i++) {
            leftProducts[i] = leftProducts[i - 1] * nums[i - 1];
        }
        
        rightProducts[n - 1] = 1;
        for (int i = n - 2; i >= 0; i--) {
            rightProducts[i] = rightProducts[i + 1] * nums[i + 1];
        }
        
        for (int i = 0; i < n; i++) {
            result[i] = leftProducts[i] * rightProducts[i];
        }
        
        return result;
    }
}

Try It Yourself

Loading code editor...

Frequently Asked Questions

How to solve LeetCode 238 (Product of Array Except Self)?

This page provides optimized solutions for LeetCode problem 238 (Product of Array Except Self) in Java, C++, and Python, along with a detailed explanation and an interactive code editor to test your code.

What is the time complexity of LeetCode 238 (Product of Array Except Self)?

The time complexity for LeetCode 238 (Product of Array Except Self) varies by solution. Check the detailed explanation section for specific complexities in Java, C++, and Python implementations.

Can I run code for LeetCode 238 on DevExCode?

Yes, DevExCode provides an interactive code editor where you can write, test, and run your code for LeetCode 238 in Java, C++, or Python.

Back to LeetCode Solutions