save project

my_search.py

@@ -5,5 +5,17 @@ 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):
+    low = 0
\ No newline at end of file
+    high = len(alist)-1
+    a = (low + high)//2
+    while low<=high:
+        if alist[a] == num:
+            return alist[a]
+        elif alist[a]<num:
+            low = a+1
+        else:
+            high = a-1
+    return None
+s = binary_search(alist,num)
+print(s)
\ No newline at end of file