Flatten a nested numeric array
Flatten a nested array of numbers into a numeric array in left-to-right depth-first order. Empty nested arrays contribute no elements. Inputs are valid JSON and must not be modified unless the algorithm uses a local copy. This exercise probes typed data modeling, boundary handling, and algorithm selection.
Input
One JSON value: Nested[]. See the sample for its exact shape.
Output
One compact JSON value of type number[]. Strings include JSON quotes; arrays preserve the specified order.
Constraints
Array/string lengths are 0 to 10000 unless stated otherwise. Numbers are integers in [-1000000,1000000]; all computed results fit the safe integer range. Nested inputs have depth at most 100.
Example
Input
[1,[2,[3]],4]
Output
[1,2,3,4]
Example 2 input
[[1,2],[],[3,[4]]]
Output
[1,2,3,4]
Checks a boundary or contrasting case beyond the public examples.
Public test cases (2)
Input
[1,[2,[3]],4]
Expected output
[1,2,3,4]
Input
[]
Expected output
[]
Hints (2)
- Start with the required output order and the empty-input behavior.
- Recurse only for array nodes and append numeric leaves
Target complexity: time O(n) · space O(n+d)