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Multiply Array

Published at10 Jan 2026
Created by
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This problem asks for the product of all numbers in the array. Instead of adding them together, you multiply them one by one until every element has been included.

A zero matters a lot here because once the array contains a zero, the whole product becomes zero. Negative values matter too, since multiplying by a negative number flips the sign of the result.

For example, if nums = [1,2,3,4], the answer is 24. If nums = [5,0,10], the answer is 0 because the zero wipes out the entire product. With nums = [-1,5], the answer is -5.

So the task is to multiply every element in the array and return the final product.

Example Input & Output

Example 1
Input
nums = [1, 2, 3, 4]
Output
24
Explanation

Example 1: Product of [1, 2, 3, 4] is 24

Example 2
Input
nums = [5, 0, 10]
Output
0
Explanation

Example 2: Product is 0 when array contains 0

Example 3
Input
nums = [2, 3]
Output
6
Explanation

Example 3: Product of [2, 3] is 6

Algorithm Flow

Recommendation Algorithm Flow for Multiply Array
Recommendation Algorithm Flow for Multiply Array

Solution Approach

The direct solution is to walk through the array while keeping a running product.

We begin with 1 because multiplying by 1 does not change the result:

let product = 1;

Then multiply each number into it:

for (const num of nums) {
  product *= num;
}

Each step updates the running product to include one more array element.

At the end, return the accumulated result:

return product;

This handles zeros, negatives, and positive numbers naturally. The time complexity is O(n), and the extra space complexity is O(1).

Best Answers

java
class Solution {
    public long multiply_array(int[] nums) {
        if (nums == null || nums.length == 0) return 0;
        long product = 1;
        for (int num : nums) product *= num;
        return product;
    }
}