save project

my_search.py

@@ -5,5 +5,21 @@ 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
+    high=len(alist)-1
+    while high >= low:
+        mid=(low+high)//2
+        guess_num=alist[mid]
+        if num == guess_num:
+            return mid
+        else:
+            if guess_num < num:
+                low = mid + 1
+            else:
+                high = mid - 1
+    return None
+result = binary_search(alist,num)
+print(result)
+
+