JSFiddle - React, Tailwind, and code Playground

by luka kupunia

JavaScript

function matrixSum(arr) {
  let matrixNums = [];
  for(let i = 0; i < arr.length; i++) {
  	matrixNums.push(arr[i][i],arr[i][arr[i].length - (i + 1)])
  }
  if(matrixNums.length % 2 === 0) {
  	matrixNums.splice(matrixNums.length / 2 - 1, 1)
  }
  console.log(matrixNums)
  return matrixNums.reduce((a,b) => a + b)
}
matrixSum([
  [1, 2, 3],
  [4, 5, 6],
  [7, 8, 9],
])