matrix-addition

function matrixAddition(a, b) {
  
  let res = [];
  for (let i = 0; i < a.length; i++) {
    res[i] = [];
    for (let j = 0; j < b.length; j++) {        
      res[i][j] = a[i][j] + b[i][j];
    }
  }
  
  return res;
}

/*
Write a function that accepts two square matrices (N x N two dimensional arrays), and return the sum of the two. Both matrices being passed into the function will be of size N x N (square), containing only integers.

How to sum two matrices:

Take each cell [n][m] from the first matrix, and add it with the same [n][m] cell from the second matrix. This will be cell [n][m] of the solution matrix.

Visualization:

|1 2 3|     |2 2 1|     |1+2 2+2 3+1|     |3 4 4|
|3 2 1|  +  |3 2 3|  =  |3+3 2+2 1+3|  =  |6 4 4|
|1 1 1|     |1 1 3|     |1+1 1+1 1+3|     |2 2 4|
*/