save project

my_search.py

 import random
-
 alist = []
 for i in range(1, 101):
     alist.append(i)
 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):
\ No newline at end of file
+def binary_search(alist,num): 
+    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
+print(binary_search(alist,num))
\ No newline at end of file