update readme, add code comment, rename script

yennanliu · Feb 23, 2024 · 25b9da4 · 25b9da4
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diff --git a/README.md b/README.md
@@ -185,9 +185,9 @@
 ||Bubble sort| [Python](./algorithm/python/bubble_sort.py), [JS](./algorithm/js/bubble_sort.js) , [C](./algorithm/c/bubble_sort.c)| | | | | OK* (3)|  
 ||Insertion sort| [Python](./algorithm/python/insertion_sort.py), [JS](./algorithm/js/insertion_sort.js) |`stable` sort| work very fast for `nearly sorted` array| | | AGAIN| 
 ||Bucket sort| [Python](./algorithm/python/bucket_sort.py)  | | | | | AGAIN| 
-||Quick sort| [quick_sort.py](./algorithm/python/quick_sort.py), [quick_sort_v2.py](./algorithm/python/quick_sort_v2.py), [QuickSort.java](https://github.com/yennanliu/CS_basics/blob/master/leetcode_java/src/main/java/AlgorithmJava/QuickSort.java)| NOTE !!!, avg is NLogN, worst is N**2, [complexity ref](https://www.geeksforgeeks.org/time-and-space-complexity-analysis-of-quick-sort/) | `Best : O(N Log N), Avg : O(N Log N), Worst : O(N^2)` | | AGAIN***| 
+||Quick sort| [quick_sort.py](./algorithm/python/quick_sort.py), [quick_sort_v2.py](./algorithm/python/quick_sort_v2.py), [QuickSort.java](https://github.com/yennanliu/CS_basics/blob/master/leetcode_java/src/main/java/AlgorithmJava/QuickSort.java)| NOTE !!!, `avg is NLogN, worst is N**2`, [big O ref](https://www.geeksforgeeks.org/time-and-space-complexity-analysis-of-quick-sort/), [big O ref 2](https://rust-algo.club/sorting/quicksort/) | `Best : O(N Log N), Avg : O(N Log N), Worst : O(N^2)` | | AGAIN***| 
 ||Heap sort| [Python](./algorithm/python/heap_sort.py)| | | AGAIN**| 
-||Merge sort|[merge_sort_topdown.py](./algorithm/python/merge_sort_topdown.py), [mergesort_bottomup.py](./algorithm/python/mergesort_bottomup.py), [MergeSortTopDown.java](https://github.com/yennanliu/CS_basics/blob/master/leetcode_java/src/main/java/AlgorithmJava/MergeSortTopDown.java), [SQL](./algorithm/sql/Mergesort.sql) | | | | | OK* (2)| 
+||Merge sort|[merge_sort_topdown.py](./algorithm/python/merge_sort_topdown.py), [mergesort_bottomup.py](./algorithm/python/merge_sort_bottomup.py), [MergeSortTopDown.java](https://github.com/yennanliu/CS_basics/blob/master/leetcode_java/src/main/java/AlgorithmJava/MergeSortTopDown.java), [SQL](./algorithm/sql/Mergesort.sql) | | | `Best : O(N Log N), Avg : O(N Log N), Worst : O(N Log N)` | O(N)| OK* (2)| 
 ||Pancake sort| [Python](./algorithm/python/pancake_sort.py) | | | | | AGAIN| 
 ||Selection sort| [Python](./algorithm/python/selection_sort.py), [JS](./algorithm/js/selection_sort.js) | | | | |  AGAIN| 
 ||Topological sort| [Python](./algorithm/python/topological_sort.py) | | Topological Sort is a algorithm can find "ordering" on an "order dependency" graph | | | AGAIN| 

diff --git a/algorithm/python/mergesort_bottomup.py → algorithm/python/merge_sort_bottomup.py b/algorithm/python/mergesort_bottomup.py → algorithm/python/merge_sort_bottomup.py
@@ -1,12 +1,24 @@
 #---------------------------------------------------------------
-# MERGE SORT bottomup
+# MERGE SORT - bottomup
 #---------------------------------------------------------------
 
 # https://leetcode.com/explore/learn/card/recursion-ii/470/divide-and-conquer/2868/
 # https://leetcode.com/problems/sort-an-array/discuss/568255/Python-Merge-Sort
+# https://rust-algo.club/sorting/mergesort/
 
-# time : O(N log N)
-# space : O(N)
+"""
+
+Time complexity
+
+Best : O(N Log N)
+Avg : O(N Log N)
+Worst : O(N Log N)`
+
+
+Space complexity
+
+O(N)
+"""
 
 class Solution:
     def sortArray(self, nums: List[int]) -> List[int]:

diff --git a/algorithm/python/merge_sort_topdown.py b/algorithm/python/merge_sort_topdown.py
@@ -1,11 +1,23 @@
 #---------------------------------------------------------------
-# MERGE SORT topdown
+# MERGE SORT - topdown
 #---------------------------------------------------------------
 
 # https://leetcode.com/explore/learn/card/recursion-ii/470/divide-and-conquer/2868/
+# https://rust-algo.club/sorting/mergesort/
 
-# time : O(N)
-# space : O(N)
+"""
+
+Time complexity
+
+Best : O(N Log N)
+Avg : O(N Log N)
+Worst : O(N Log N)`
+
+
+Space complexity
+
+O(N)
+"""
 
 def merge_sort(nums):
     # bottom cases: empty or list of a single element.

diff --git a/algorithm/python/quick_sort.py b/algorithm/python/quick_sort.py
@@ -2,6 +2,24 @@
 # QUICK SORT V1
 #---------------------------------------------------------------
 
+"""
+
+Time complexity
+
+Best    O(n log n)
+Average O(n log n)
+Worst   O(n^2) 
+
+
+
+Space complexity
+
+Worst space $O(log n) $ or $O(n) $ auxiliary
+
+"""
+
+# https://rust-algo.club/sorting/quicksort/index.html
+
 # V0
 # https://www.bilibili.com/video/BV1at411T75o/
 # https://hackmd.io/@Aquamay/H1nxBOLcO/https%3A%2F%2Fhackmd.io%2F%40Aquamay%2FB1SPnfRq_
@@ -202,4 +220,4 @@ def three_way_radix_quicksort(sorting: list) -> list:
         three_way_radix_quicksort([i for i in sorting if i < sorting[0]])
         + [i for i in sorting if i == sorting[0]]
         + three_way_radix_quicksort([i for i in sorting if i > sorting[0]])
-    )
+    )
diff --git a/algorithm/python/quick_sort_v2.py b/algorithm/python/quick_sort_v2.py
@@ -3,6 +3,23 @@
 #---------------------------------------------------------------
 
 # https://leetcode.com/explore/learn/card/recursion-ii/470/divide-and-conquer/2870/
+# https://rust-algo.club/sorting/quicksort/index.html
+
+"""
+
+Time complexity
+
+Best    O(n log n)
+Average O(n log n)
+Worst   O(n^2) 
+
+
+
+Space complexity
+
+Worst space $O(log n) $ or $O(n) $ auxiliary
+
+"""
 
 def quicksort(lst):
     """