modify sth

lambdaplus · lambdaplus · commit 2b5e13ff5134 · 2016-12-05T17:46:28.000+08:00
diff --git a/Algorithm/sort/bubble-sort.py b/Algorithm/sort/bubble-sort.py
@@ -7,14 +7,15 @@ def bubble_sort(L):
     冒泡排序主要使用两次循环实现排序。
     外循环中的一个数字依次与内层循环中的每个数字进行比较，如果索引值小的数字大于索引值大的数字，交换位置。否则，位置不变。直至外循环结束。
     '''
-    if len(L) < 2: # 列表内元素低于2，直接返回！
+    if len(L) < 2:  # 列表内元素低于2，直接返回！
         return L
     for i in range(len(L)):
         for j in range(1, len(L)):
             if L[j - 1] > L[j]:
                 L[j - 1], L[j] = L[j], L[j - 1]
     return L
 
+
 if __name__ == '__main__':
     L = [randrange(1000) for _ in range(10)]
     print(bubble_sort(L))
diff --git a/Algorithm/sort/insert_sort.py b/Algorithm/sort/insert_sort.py
@@ -1,9 +1,12 @@
 # coding=utf-8
+
 from random import randrange
 
+
 def insert_sort(L):
     if len(L) < 2:
         return L
+
     for i in range(1, len(L)):
         tmp = L[i]
         j = i - 1
@@ -14,6 +17,6 @@ def insert_sort(L):
 
     return L
 
-#if __name__ == '__main__':
+# if __name__ == '__main__':
 #    L = [randrange(1000) for _ in range(10)]
 #    print(insert_sort(L))
diff --git a/Algorithm/sort/merge/merge-sort.py b/Algorithm/sort/merge/merge-sort.py
@@ -1,6 +1,7 @@
 # -*-coding: utf-8 -*-
 from random import randrange
 
+
 def merge_sort(L):
     if len(L) < 2:
         return L
@@ -16,14 +17,41 @@ def merge(left, right):
 
         while right:
             merged.append(right.pop(0))
-        
+
         return merged
 
-    mid = int(len(L)/2)
+    mid = int(len(L) / 2)
     left = merge_sort(L[:mid])
     right = merge_sort(L[mid:])
     return merge(left, right)
 
+
 if __name__ == "__main__":
     L = [randrange(1000) for _ in range(10)]
     print(merge_sort(L))
+
+# Another
+from random import randrange
+
+
+def merge_sort(seq):
+    mid = len(seq) // 2
+    lft, rgt = seq[:mid], seq[mid:]
+    if len(lft) > 1:
+        lft = merge_sort(lft)
+    if len(rgt) > 1:
+        rgt = merge_sort(rgt)
+
+    res = []
+    while lft and rgt:
+        if lft[-1] >= rgt[-1]:  # 取lft和rgt序列中最大的值
+            res.append(lft.pop())
+        else:
+            res.append(rgt.pop())
+    res.reverse()              # 反序一下
+    return (lft or rgt) + res
+
+
+if __name__ == '__main__':
+    seq = [randrange(100) for _ in range(10)]
+    print(merge_sort(seq))
diff --git a/Algorithm/sort/merge/merge-sort1.py b/Algorithm/sort/merge/merge-sort1.py
@@ -21,15 +21,18 @@
     >>> list(merge(['dog', 'horse'], ['cat', 'fish', 'kangaroo'], key=len))
     ['dog', 'cat', 'fish', 'horse', 'kangaroo']
 '''
+
+
 def merge_sort(L):
     if len(L) < 2:
         return L
 
-    mid = int(len(L)/2)
+    mid = int(len(L) / 2)
     left = merge_sort(L[:mid])
     right = merge_sort(L[mid:])
     return list(merge(left, right))
 
+
 if __name__ == "__main__":
     L = [randrange(100) for _ in range(10)]
     print(merge_sort(L))
diff --git a/Algorithm/sort/merge/merge-sort2.py b/Algorithm/sort/merge/merge-sort2.py
@@ -0,0 +1,25 @@
+# coding=utf-8
+from random import randrange
+
+
+def merge_sort(seq):
+    mid = len(seq) // 2
+    lft, rgt = seq[:mid], seq[mid:]
+    if len(lft) > 1:
+        lft = merge_sort(lft)
+    if len(rgt) > 1:
+        rgt = merge_sort(rgt)
+
+    res = []
+    while lft and rgt:
+        if lft[-1] >= rgt[-1]:  # 取lft和rgt序列中最大的值
+            res.append(lft.pop())
+        else:
+            res.append(rgt.pop())
+    res.reverse()              # 反序一下
+    return (lft or rgt) + res
+
+
+if __name__ == '__main__':
+    seq = [randrange(100) for _ in range(10)]
+    print(merge_sort(seq))
diff --git a/Algorithm/sort/quick-sort.py b/Algorithm/sort/quick-sort.py
@@ -1,6 +1,7 @@
 # coding=utf-8
 import random
 
+
 def quick_sort(seq):
     if len(seq) < 2:
         return seq
@@ -10,6 +11,7 @@ def quick_sort(seq):
     big = [x for x in seq if x > mid]
     return quick_sort(small) + [mid] + quick_sort(big)
 
+
 if __name__ == '__main__':
     L = [random.randrange(1000) for _ in range(10)]
     print(quick_sort(L))
