Imagine an array that contains both integers and nested arrays, such as the following:[8, 4, [5, [9], 3], 6].
The depth sum is described as the weighted sum of each integer, weighted by their respective depths. In the example, 8’s depth is 1, while 9’s is 3.
Given such an array, calculate its depth sum.
Examples
- Input:
[4, [5, 6]]
Output:4*1 + 2*5 + 2*6 = 26 - Input:
[8, 4, [5, [9], 3], 6]
Output:8*1 + 4*1 + 2*5 + 3*9 + 2*3 + 1*6 = 61
Summary (with approach)
Traverse the nested list with DFS/BFS carrying the current depth d.
- If it’s an integer:
sum += d * val; - If it’s a list: recurse/enqueue with
d+1.
Time O(N) over all elements; space O(H) for recursion/queue depth.
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