Detecting the Largest Element in an Array of Numbers (nested) in JavaScript

Given a nested array of numbers, we need to find and return the largest element present in the array.

Below are the approaches to detecting the largest element in an array of Numbers (nested) in JavaScript:

Iterative Approach

• Use a nested loop to traverse through each element of the array and its subarrays.
• Keep track of the largest element found so far and initialize it to the smallest possible value.
• During traversal, if an element is larger than the current largest, update the largest element.
• Continue traversing until all elements in the nested array have been visited.
• Return the largest element found after completing the traversal.

const nestedArray = [1, [2, 3, [4, 5], 6], [7, 8], 9];

function maxIterative(arr) {
    let largest = Number.MIN_SAFE_INTEGER;
    for (let i = 0; i < arr.length; i++) {
        if (Array.isArray(arr[i])) {
            largest = Math.max(largest, maxIterative(arr[i]));
        } else {
            largest = Math.max(largest, arr[i]);
        }
    }
    return largest;
}

console.log(maxIterative(nestedArray)); 

9

Time Complexity: Time complexity of O(n), where n is the total number of elements in the nested array.

Space Complexity: The space complexity is also O(n).

Recursive Approach

• Recursively traverse through each element of the array and its subarrays.
• Initialize a variable to keep track of the largest element found so far and set it to the smallest possible value.
• At each step of recursion, compare the current element with the largest element found so far.
• If the current element is larger, update the largest element accordingly.
• Continue the recursion until all elements in the nested array have been visited.
• Return the largest element found after completing the recursion.

const nestedArray = [1, [2, 3, [4, 5], 6], [7, 8], 9];

function largestRecursive(arr) {
  let largest = Number.MIN_SAFE_INTEGER; 
  arr.forEach(element => {
    if (Array.isArray(element)) { 
      largest = Math.max(largest, largestRecursive(element)); 
    } else {
      largest = Math.max(largest, element); 
    }
  });
  return largest; 
}

console.log(largestRecursive(nestedArray)); 

9

Time Complexity: Time complexity of O(n), where n is the total number of elements in the nested array.

Space Complexity: The space complexity is also O(n).

Conclusion

The purpose of these methods is to discover the largest element in an embedded array by either iterating or recursively pursuing the individual element and update the largest element as long as are found elements that are larger than the found one so far. The iterative or recursive approach often is chosen by the programmer's personal preference unlike the other one, as well as the specification of the problem to be solved.