归并排序

Author: qiwsir

merge_sort.md

@@ -53,84 +53,84 @@
 
 #解决(Python)
 
-#! /usr/bin/env python
-#coding:utf-8
-
-#方法1：将前面讲述的过程翻译过来了，略先拙笨
-
-def merge_sort(seq):
-    if len(seq) ==1:
-        return seq
-    else:
-        middle = len(seq)/2
-        left = merge_sort(seq[:middle])
-        right = merge_sort(seq[middle:])
-
-        i = 0   #left 计数
-        j = 0   #right 计数
-        k = 0   #总计数
-
-        while i < len(left) and j < len(right):
-            if left[i] < right [j]:
-                seq[k] = left[i]
-                i +=1
-                k +=1
-            else:
-                seq[k] = right[j]
-                j +=1
-                k +=1
-        
-        remain = left if i<j else right
-        r = i if remain ==left else j
-
-        while r<len(remain):
-            seq[k] = remain[r]
-            r +=1
-            k +=1
-
-        return seq
-
-#方法2：在按照顺序取数值方面，应用了list.pop()方法，代码更紧凑简洁
-#此方法来[自维基百科：归并操作](http://zh.wikipedia.org/zh/%E5%BD%92%E5%B9%B6%E6%8E%92%E5%BA%8F)
-
-def merge_sort(lst):   #此方法来自维基百科：http://zh.wikipedia.org/zh/%E5%BD%92%E5%B9%B6%E6%8E%92%E5%BA%8F
-    if len(lst) <= 1:
-        return lst
-                 
-    def merge(left, right):
-        merged = []
-        
-        while left and right:
-            merged.append(left.pop(0) if left[0] <= right[0] else right.pop(0))
-        
-        while left:
-            merged.append(left.pop(0))
-        
-        while right:
-            merged.append(right.pop(0))
-        
-        return merged
-        
-    middle = int(len(lst) / 2) 
-    left = merge_sort(lst[:middle])
-    right = merge_sort(lst[middle:])
-    return merge(left, right)
-
-#方法3：原来在python的模块heapq中就提供了归并排序的方法，只要将分解后的结果导入该方法即可
-#强大。
-#以下方法来自[resettacode](http://rosettacode.org/wiki/Sorting_algorithms/Merge_sort#Python),并稍作修改
-
-from heapq import merge
- 
-def merge_sort(seq):
-    if len(seq) <= 1:
-        return m
-    else:              
-        middle = len(seq)/2
-        left = merge_sort(seq[:middle])
-        right = merge_sort(seq[middle:])
-        return list(merge(left, right))         #heapq.merge()
-
-if __name__=="__main__":
-    seq = [1,3,6,2,4]
-    print merge_sort(seq)
+	#! /usr/bin/env python
+	#coding:utf-8
+	
+	#方法1：将前面讲述的过程翻译过来了，略先拙笨
+	
+	def merge_sort(seq):
+	    if len(seq) ==1:
+	        return seq
+	    else:
+	        middle = len(seq)/2
+	        left = merge_sort(seq[:middle])
+	        right = merge_sort(seq[middle:])
+	
+	        i = 0   #left 计数
+	        j = 0   #right 计数
+	        k = 0   #总计数
+	
+	        while i < len(left) and j < len(right):
+	            if left[i] < right [j]:
+	                seq[k] = left[i]
+	                i +=1
+	                k +=1
+	            else:
+	                seq[k] = right[j]
+	                j +=1
+	                k +=1
+	        
+	        remain = left if i<j else right
+	        r = i if remain ==left else j
+	
+	        while r<len(remain):
+	            seq[k] = remain[r]
+	            r +=1
+	            k +=1
+	
+	        return seq
+	
+	#方法2：在按照顺序取数值方面，应用了list.pop()方法，代码更紧凑简洁
+	#此方法来[自维基百科：归并操作](http://zh.wikipedia.org/zh/%E5%BD%92%E5%B9%B6%E6%8E%92%E5%BA%8F)
+	
+	def merge_sort(lst):   #此方法来自维基百科：http://zh.wikipedia.org/zh/%E5%BD%92%E5%B9%B6%E6%8E%92%E5%BA%8F
+	    if len(lst) <= 1:
+	        return lst
+	                 
+	    def merge(left, right):
+	        merged = []
+	        
+	        while left and right:
+	            merged.append(left.pop(0) if left[0] <= right[0] else right.pop(0))
+	        
+	        while left:
+	            merged.append(left.pop(0))
+	        
+	        while right:
+	            merged.append(right.pop(0))
+	        
+	        return merged
+	        
+	    middle = int(len(lst) / 2) 
+	    left = merge_sort(lst[:middle])
+	    right = merge_sort(lst[middle:])
+	    return merge(left, right)
+	
+	#方法3：原来在python的模块heapq中就提供了归并排序的方法，只要将分解后的结果导入该方法即可
+	#强大。
+	#以下方法来自[resettacode](http://rosettacode.org/wiki/Sorting_algorithms/Merge_sort#Python),并稍作修改
+	
+	from heapq import merge
+	 
+	def merge_sort(seq):
+	    if len(seq) <= 1:
+	        return m
+	    else:              
+	        middle = len(seq)/2
+	        left = merge_sort(seq[:middle])
+	        right = merge_sort(seq[middle:])
+	        return list(merge(left, right))         #heapq.merge()
+	
+	if __name__=="__main__":
+	    seq = [1,3,6,2,4]
+	    print merge_sort(seq)