Merge pull request #744 from neha030/dev19

Selection Sort added

Author: Saviour1001

Sorting Algorithms/SelectionSort.js

@@ -0,0 +1,53 @@
+/*SELECTION SORT: 
+    * inplace comparison-based sorting algorithm.
+    * list is divided into two parts, the sorted part at the left end and the unsorted part at the right end. 
+    * The smallest element from the unsorted array is found and swapped with the leftmost element.
+      ie, added to the sorted array. 
+    * This process continues moving unsorted array boundary by one element to the right.
+*/
+
+//importing readline module for dynamic input 
+var readline = require('readline');
+//initialising inputstream and outstream to process.stdin and process.stdout respectively.
+var rl = readline.createInterface(
+    process.stdin, process.stdout);
+
+const selectionSort = (arr) => {
+    let n = arr.length;
+    // i is the current index
+    for(let i=0; i<n-1; i++){
+        //minPos stores the position of smallest element
+        let minPos = i;
+
+        //finding the minimum element from arr.
+        for(let j=i+1; j<n; j++){
+            if(arr[j] < arr[minPos]){
+                minPos = j;
+            }
+        }
+        //swapping current element and smallest element;
+        let temp = arr[minPos];
+        arr[minPos] = arr[i];
+        arr[i] = temp;
+    }
+    return arr;
+}
+
+//Reading input from console as a string and converting it to array 
+rl.question('Enter array elements comma separated: ', (input) => {
+    let numbers = input.split(",");
+    numbers = numbers.map( (x) => parseInt(x));
+    console.log(selectionSort(numbers));
+    rl.close();
+});
+
+/*
+INPUT
+Enter array elements comma separated: 
+1, 8, 7, 61, 5, 4, 11
+OUTPUT
+1,4,5,7,8,11,61
+
+    Time Complexity - O(n^2)
+    Space Complexity - O(1)
+*/