Selection Sort

Q. Write an algorithm that performs selection sort on a given array.

let nums = [3, 2, 1];
const selectionSort = function (arr) {
 for (let i = 0; i < arr.length - 1; i++) {
  let minIndex = i;
  for (let j = i + 1; j < arr.length; j++) {
   if (arr[j] < arr[minIndex]) {
    minIndex = j;
   }
  }
  [arr[i], arr[minIndex] = [arr[minIndex], arr[i]];
 }
 return arr;
}
console.log(selectionSort(nums));
// should be [ 1, 2, 3]

1. Declare minIndex is equal to i.
2. If arr[j] is less than arr[minIndex], return minIndex is equal to j.
3. Iterate 2. until j become to be equal to arr.length-1. (Which means it would be conditioned j < arr.length)
4. arr[i] , arr[minIndex] will be arr[minIndex], arr[i].
5. Iterate 1. - 4. until i become to be equal to arr.length-2. (Which means it would be conditioned i < arr.length-1)

1st loop (i)
i = 0
minIndex = 0
1st loop (j)
j = 0
arr[0] < arr[0] // ? 3 < 3 // False
2nd loop (j)
j = 1
arr[1] < arr[0] // ? 2 < 3 // True
minIndex = 1
3rd loop (j)
j = 2
arr[2] < arr[1] // ? 1 < 3 // True
minIndex = 2

[arr[i], arr[minIndex]] = [arr[minIndex], arr[i]]
[3, 2, 1] = [1, 2, 3]