Update READMEs.

Author: trekhleb

README.md

@@ -229,14 +229,14 @@ Below is the list of some of the most used Big O notations and their performance
 
 ### Array Sorting Algorithms Complexity
 
-| Name | Best | Average | Worst | Memory | Stable | Comments |
-| --------------------- | :-------: | :-------: | :-----------: | :-------: | :-------: | :-------- |
-| **Bubble sort** | n | n<sup>2</sup> | n<sup>2</sup>  | 1 | Yes | |
-| **Insertion sort** | n | n<sup>2</sup> | n<sup>2</sup>  | 1 | Yes | |
-| **Selection sort** | n<sup>2</sup>  | n<sup>2</sup> | n<sup>2</sup>  | 1 | No | |
-| **Heap sort** | n log(n) | n log(n) | n log(n) | 1 | No | |
-| **Merge sort** | n log(n) | n log(n) | n log(n) | n | Yes | |
-| **Quick sort** | n log(n) | n log(n) | n<sup>2</sup>  | log(n) | No | |
-| **Shell sort** | n log(n) | depends on gap sequence | n (log(n))<sup>2</sup> | 1 | No | |
-| **Counting sort** | n + r | n + r | n + r | n + r | Yes | r - biggest number in array |
-| **Radix sort** | n * k | n * k | n * k | n + k | Yes  | k - length of longest key |
+| Name | Best  | Average  | Worst  | Memory | Stable | Comments |
+| --------------------- | :-------------: | :-----------------: | :-----------------: | :-------: | :-------: | :-------- |
+| **Bubble sort** | n  | n<sup>2</sup> | n<sup>2</sup> | 1 | Yes | |
+| **Insertion sort** | n  | n<sup>2</sup> | n<sup>2</sup> | 1 | Yes | |
+| **Selection sort** | n<sup>2</sup> | n<sup>2</sup> | n<sup>2</sup> | 1 | No | |
+| **Heap sort** | n log(n)  | n log(n)  | n log(n)  | 1 | No | |
+| **Merge sort** | n log(n)  | n log(n)  | n log(n)  | n | Yes | |
+| **Quick sort** | n log(n)  | n log(n)  | n<sup>2</sup> | log(n) | No | |
+| **Shell sort** | n log(n)  | depends on gap sequence | n (log(n))<sup>2</sup> | 1 | No  | |
+| **Counting sort** | n + r  | n + r  | n + r  | n + r | Yes | r - biggest number in array |
+| **Radix sort** | n * k  | n * k  | n * k  | n + k  | Yes | k - length of longest key |