save project

my_search.py

@@ -7,3 +7,15 @@ 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
 # 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):
 def binary_search(alist,num):
+    low=0
+    high=len(alist)-1
+    while high>=low:
+        mid=(low+high)//2
+        if alist[mid]==num:
+            return mid
+        if alist[mid]<num:
+            low=mid+1
+        else:
+            high=mid+1
+    return None
+    print(ef(alist,num))