feat: add counting sort

Related: #14

Sorts/countingSort.js

@@ -0,0 +1,37 @@
+/*
+ * Counting sort is an algorithm for sorting a collection of objects according to keys that are small integers;
+ * that is, it is an integer sorting algorithm.
+ * more information: https://en.wikipedia.org/wiki/Counting_sort
+ * counting sort visualization: https://www.cs.usfca.edu/~galles/visualization/CountingSort.html
+ */
+
+function countingSort(arr, min, max) {
+  let i;
+  let z = 0;
+  const count = [];
+  
+  for (i = min; i <= max; i++) {
+    count[i] = 0;
+  }
+  
+  for (i = 0; i < arr.length; i++) {
+    count[arr[i]]++;
+  }
+  
+  for (i = min; i <= max; i++) {
+    while (count[i]-- > 0) {
+      arr[z++] = i;
+    }
+  }
+  
+  return arr;
+}
+
+const arr = [3, 0, 2, 5, 4, 1];
+
+// Array before Sort
+console.log("-----before sorting-----");
+console.log(arr);
+// Array after sort
+console.log("-----after sorting-----");
+console.log(countingSort(arr, 0, 5));