save project

my_search.py

 import random
 import random
 
 
-alist = []
+alist = [] 
 for i in range(1, 101):
 for i in range(1, 101):
     alist.append(i)
     alist.append(i)
 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 high<low:
+        mid =(low+high)//2
+        a=alist[mid]
+        if a == num:
+            return mid
+        elif a<num:
+            low = mid+1
+        else:
+            high = mid-1
+    return None
+b=binary_search(alist,num)
+print(b)
\ No newline at end of file