added counting sort repo

countingsort.js

@@ -0,0 +1,22 @@
+let countingSort = (arr, min, max) => {
+    let i = min,
+        j = 0,
+        len = arr.length,
+        count = [];
+    for (i; i <= max; i++) {
+        count[i] = 0;
+    }
+    for (i = 0; i < len; i++) {
+        count[arr[i]] += 1;
+    }
+    for (i = min; i <= max; i++) {
+        while (count[i] > 0) {
+            arr[j] = i;
+            j++;
+            count[i]--;
+        }
+    }
+    return arr;
+};
+
+