We will learn some of the basic and popular sorting algorithms. But before we directly jump on the topic let’s first understand some parameters used to describe/evaluate a sorting algorithm.

Time Complexity:

The time complexity of an algorithm quantifies the amount of time taken by an algorithm to run as a function of the length of the input.

Space Complexity:

The space complexity of an algorithm is the amount of memory space required to solve an instance of the computational problem as a function of the length of the input.

Stability:

Consider you have an array [2, 4, 4] & let’s rename it to [2, 4i, 4j] for understanding purpose. Some sorting algorithms will keep the 4 in its respective positions [2, 4i, 4j] while some sorting algorithms will swap the positions of 4 like [2, 4j, 4i] while sorting.

Algorithms which does not change the positions of equally-weighted numbers from their relative positions in the input are known to be Stable while algorithms which change the respective positions of numbers are known as UnStable

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1. Selection Sort

let unsorted = [5,1,8,4,9,6,7,2,3]

	swap=(array, leftIndex, rightIndex)=>{
	    var temp = array[leftIndex];
	    array[leftIndex] = array[rightIndex];
	    array[rightIndex] = temp;
	}

	selectionSort=(array)=>{
	    console.log(`Iteration 0 :`  ,array.join(' '))
	    for(let i=0; i<array.length; i++){
	        let min = i
	        for(let j=i; j<array.length; j++){
	            if(array[min]> array[j]){
	                min = j
	            }
	        }
	        swap(array, min, i) // Swap Positions
	        console.log(`Iteration ${i+1} :`  ,array.join(' '))
	    }        
	}

	selectionSort(unsorted) // Invoking Sort

Time Complexity
------------------------

Best Case    : O(n^2)
Average Case : O(n^2)
Worst Case   : O(n^2)

------------------------
Space Complexity : O(n)
Stability: Stable

Selection Sort Output

_The sorting happens in the order of the index of an array. It first selects the position of the elements & finds outs the element that belongs to that position & hence called _selection sort

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