save project

my_search.py

 import random
 import random
 
 
-alist = []
+num_alist = []
 for i in range(1, 101):
 for i in range(1, 101):
-    alist.append(i)
-num = random.choice(alist)
+    num_alist.append(i)
+num = random.choice(num_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
+        guess = alist[mid]
+        if guess == int(num):
+            return mid
+        elif guess < int(num):
+            low = mid + 1
+        elif guess > int(num):
+            high = mid - 1
+    return None
+answer = input('请给一个数：')
+print('它在列表里的索引值是：'+str(binary_search(num_alist,answer)))
+print('桃桃老师给的数是：'+str(num))
+print('它在列表里的索引值是：'+str(binary_search(num_alist,num)))