save project

my_search.py

@@ -6,4 +6,20 @@ for i in range(1, 101):
 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 = alist[mid]
+        if guess == num:
+            return mid
+        elif guess < num :
+            low = mid + 1
+        else:
+            high = mid - 1
+    return None
+
+result = binary_search(alist,num)
+print('给出的数字是'+ str(num))
+print('它的索引是' + str(result))