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# Selection sort algorithm

Selection sort is one of the simplest sorting algorithms, it works by continually finding the minimum number in the array and inserting it at the beginning.

The time complexity of selection sort is **O(n ^{2})** and it's space complexity is

**O(1)**

- itertate from 0 to len(arr) - 1
- seting to minimunIdx variable the first element index in the unsorted part
- loop trough the unsorted part
- if arr[j] < arr[minimumIdx] => minimumIdx = j
- swaping arr[minimumIdx] with the first in the unsorted part (unsortedPart[0])

```
def selectionSortAlgorithm(arr: list) -> list:
"""
[ name ] => Selecion sort
[ type ] => Sorting algorithms
[ time complexity ] => O(n^2)
[ space complexity ] => O(1)
[ params ] => ( arr {list} array to sort )
[ return ] => sorted list
[ logic ] => (
1. itertate from 0 to len(arr) - 1
2. seting to minimunIdx variable the first element index in the unsorted part
3. loop trough the unsorted part
4. if arr[j] < arr[minimumIdx] => minimumIdx = j
5. swaping arr[minimumIdx] with the first in the unsorted part (unsortedPart[0])
)
"""
# itertate from 0 to len(arr) - 1
for i in range(len(arr)):
# setting to minimunIdx variable the first element index in the unsorted part
minIdx = i
# loop trough the unsorted part
for j in range(i + 1, len(arr)):
# if arr[j] < currentMinimum (arr[minIdx])
if arr[j] < arr[minIdx]:
# minIdx will be the index of the new minimum
minIdx = j
# swaping the minimum with the first element in the unsorted part
arr[minIdx], arr[i] = arr[i], arr[minIdx]
return arr
```

```
/**
* sort an array using selection sort algorithm
* time complexity : O(n^2)
* space complexity : O(1)
* @param {Array} arr array to sort
* @returns {Array} sorted array
*/
const SelectionSortAlgorithm = (arr) => {
// iterate from 0 to arr.length - 1
for (let i = 0; i < arr.length; i++){
// setting to minimunIdx variable the first element index in the unsorted part
var minIdx = i;
// loop trough the unsorted part
for (let j = i + 1; j < arr.length; j++) {
// if arr[j] < currentMinimum (arr[minIdx])
if (arr[j] < arr[minIdx]) {
// minIdx will be the index of the new minimum
minIdx = j;
}
}
// swaping the minimum with the first element in the unsorted part
[arr[minIdx], arr[i]] = [arr[i], arr[minIdx]];
}
return arr
}
```

sort an array in descending order using the selection sort algorithm

- https://www.geeksforgeeks.org/python-program-for-selection-sort/
- https://www.programiz.com/dsa/selection-sort
- https://stackoverflow.com/questions/22898928/selection-sort-in-javascript
- https://www.youtube.com/watch?v=EnodMqJuQEo
- https://www.geeksforgeeks.org/selection-sort/
- https://www.youtube.com/watch?v=xWBP4lzkoyM

Have a good day :)

#day_10

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