construct2Darray.js

// You are given a 0-indexed 1-dimensional (1D) integer array original, and two integers, m and n. You are tasked with creating a 2-dimensional (2D) array with  m rows and n columns using all the elements from original.

// The elements from indices 0 to n - 1 (inclusive) of original should form the first row of the constructed 2D array, the elements from indices n to 2 * n - 1 (inclusive) should form the second row of the constructed 2D array, and so on.

// Return an m x n 2D array constructed according to the above procedure, or an empty 2D array if it is impossible.

 

// Example 1:


// Input: original = [1,2,3,4], m = 2, n = 2
// Output: [[1,2],[3,4]]
// Explanation: The constructed 2D array should contain 2 rows and 2 columns.
// The first group of n=2 elements in original, [1,2], becomes the first row in the constructed 2D array.
// The second group of n=2 elements in original, [3,4], becomes the second row in the constructed 2D array.
// Example 2:

// Input: original = [1,2,3], m = 1, n = 3
// Output: [[1,2,3]]
// Explanation: The constructed 2D array should contain 1 row and 3 columns.
// Put all three elements in original into the first row of the constructed 2D array.
// Example 3:

// Input: original = [1,2], m = 1, n = 1
// Output: []
// Explanation: There are 2 elements in original.
// It is impossible to fit 2 elements in a 1x1 2D array, so return an empty 2D array.


var construct2DArray = function(original, m, n) {
  if(original.length !== (m * n)) return []

  let result = []
  let ref = []

  for(let i = 0; i < original.length; i++){
      ref.push(original[i])

      if(ref.length === n){
          result.push(ref)
          ref = []
      }
  }

  return result
};