save project

my_search.py

@@ -6,4 +6,19 @@ for i in range(1, 101):
 num = random.choice(alist)
 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):
\ No newline at end of file
+    low=0
+    high=len(alist)-1
+    while low <=high:
+        mid=(low+high)//2
+        guess_num=alist[mid]
+        if guess_num==num:
+            return mid
+        elif guess_num<num:
+            low=mid+1
+        elif guess_num>num:
+            high=mid-1
+    return None
+result=binary_search(alist,num)
+print('这个数是：',num)
+print('这个数的索引是：',result)
\ No newline at end of file