Insertion sort code added

Author: me-shaon

Sorting/Insertion Sort/README.md

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+# Insertion Sort
+
+**Insertion sort** does exactly what you would expect: it inserts each element of the array into its proper position, leaving progressively larger stretches of the array sorted. What this means in practice is that the sort iterates down an array, and the part of the array already covered is in order; then, the current element of the array is inserted into the proper position at the head of the array, and the rest of the elements are moved down, using the space just vacated by the element inserted as the final space.
+
+![Insertion Sort](insertion_sort.jpg)
+
+
+#####A visualization on Insertion Sort
+![Insertion sort demonstration](https://upload.wikimedia.org/wikipedia/commons/0/0f/Insertion-sort-example-300px.gif)
+
+
+####Complexity Analysis
+- Worst Case - О(n<sup>2</sup>) comparisons, swaps
+- Average Case - О(n<sup>2</sup>) comparisons, swaps
+- Best Case - O(n) comparisons, O(1) swaps
+### More on this topic
+- https://en.wikipedia.org/wiki/Insertion_sort
+- http://quiz.geeksforgeeks.org/insertion-sort/
+- https://www.topcoder.com/community/data-science/data-science-tutorials/sorting/

Sorting/Insertion Sort/insertion-sort.js

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+//Insertion sort implementation
+function insertionSort(arr){
+    var len = arr.length;
+
+    for(var i=1; i<len; i++){
+       currentValue = arr[i];
+       j = i-1;
+
+       /* Move elements of arr[0..i-1], that are
+          greater than current_value, to one position ahead
+          of their current position */
+       while (j >= 0 && arr[j] > currentValue)
+       {
+           arr[j+1] = arr[j];
+           j--;
+       }
+       arr[j+1] = currentValue;
+    }
+
+    return arr;
+}
+
+/******************* Testing Selection sort algorithm *********************/
+
+/**
+ * Returns a random integer between min (inclusive) and max (inclusive)
+ * Using Math.round() will give you a non-uniform distribution!
+ */
+function getRandomInt(min, max) {
+    return Math.floor(Math.random() * (max - min + 1)) + min;
+}
+
+var arr = [];
+
+for(var i=0;i<10;i++){ //initialize a random integer unsorted array
+    arr.push(getRandomInt(1, 100));
+}
+
+console.log("Unsorted array: ");
+console.log(arr); //printing unsorted array
+
+arr = insertionSort(arr);
+console.log("Sorted array: ");
+console.log(arr); //printing sorted array