save project

my_search.py

@@ -5,5 +5,19 @@ for i in range(1, 101):
     alist.append(i)
 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):
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+def binary_search(alist,num):
+    low=0
+    high=len(alist)
+    while low<=high:
+        mid=(low+high)//2
+        guess_num=alist[mid]
+        if guess_num==num:
+            return mid
+        elif guess_num<num:
+            low=mid+1
+        else:
+            high=mid-1
+    return None
+result=binary_search(alist,num)
+print(num)
+print("索引:",result)
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