save project

my_search.py

@@ -7,3 +7,18 @@ num = random.choice(alist)
 # 请完善二分查找函数binary_search(),查找出num在列表alist里面的索引位置
 
 def binary_search(alist,num):
+    low = 0
+    high = len(alist)-1
+    mid = 50
+    while 1 :
+        mid=(high + low)//2
+        if alist[mid] == num:
+            return mid
+        elif alist[mid] > num:
+            high = mid-1
+        else :
+            low = mid+1
+        if low>=high:
+            return None
+
+print(binary_search(alist,46))
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