Podcast Summary
Product of array except self: Create left prefix and right suffix arrays to find product of all elements except self in an array without division or extra space in O(n) time complexity
When trying to find the product of all elements in an array except the self-element without using division or extra space, an effective approach is to create two additional arrays, one for the left prefix product and another for the right suffix product. By iterating through the array, we can calculate the left prefix product and right suffix product using multiplication. The left prefix product at each index is the product of the current element and the previous element in the array. The right suffix product at each index is the product of the element at the current index and all the subsequent elements in the array. The final result can be obtained by multiplying the left prefix product and the right suffix product, and subtracting the self-element from the product at the corresponding index. This algorithm runs in O(n) time complexity and does not use the division operation. It's an interesting algorithmic problem that requires creative problem-solving and an understanding of array manipulation.
Array product without extra space: By using the output array itself to store intermediate results, we can calculate the product of an array except for the current element using only constant space
The discussion revolves around finding a solution to calculate the product of an array except for the current element, with the constraint of using constant space. The initial approach involved using two auxiliary arrays, but the output array itself doesn't count as additional space, making it a clever trick. The logic behind the solution was explained with an example, but the challenge was to adapt it to use only constant space. The code provided in the discussion achieves this by slightly modifying the logic, giving a result that is almost the same as the previous solution.