2649. Nested Array Generator

Problem

Given a multi-dimensional array of integers, return a generator object which yields integers in the same order as inorder traversal.

A multi-dimensional array is a recursive data structure that contains both integers and other multi-dimensional arrays.

inorder traversal iterates over each array from left to right, yielding any integers it encounters or applying inorder traversal to any arrays it encounters.

Example 1:

Input: arr = [[[6]],[1,3],[]]
Output: [6,1,3]
Explanation:
const generator = inorderTraversal(arr);
generator.next().value; // 6
generator.next().value; // 1
generator.next().value; // 3
generator.next().done; // true

Example 2:

Input: arr = []
Output: []
Explanation: There are no integers so the generator doesn't yield anything.

Constraints:

• 0 <= arr.flat().length <= 105
• 0 <= arr.flat()[i]&nbsp;<= 105
• maxNestingDepth <= 105

Can you solve this without creating a new flattened version of the array?

Solution (Javascript)

/**
 * @param {Array} arr
 * @return {Generator}
 */
var inorderTraversal = function* (arr) {
  for (let element of arr) {
    if (Array.isArray(element)) {
      yield* inorderTraversal(element);
    } else {
      yield element;
    }
  }
};

/**
 * const gen = inorderTraversal([1, [2, 3]]);
 * gen.next().value; // 1
 * gen.next().value; // 2
 * gen.next().value; // 3
 */

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).