save project

my_search.py

@@ -7,3 +7,19 @@ 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 low <= high:
+        mid = (low + high) // 2
+        guess = alist[mid]
+        if guess == num:
+            return mid
+        elif guess < num:
+            low = mid + 1
+        elif guess > num:
+            high = mid - 1
+    return None
+result = binary_search(alist,num)
+print("老师给的数是：",num)
+print("它在列表的索引是",result)
+