save project

my_search.py

@@ -5,5 +5,20 @@ 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):
+    low = 0
+    high = len(alist)-1
+    while low <= high:
+        mid = (low+high) // 2 #取中间的索引位置   //取整
+        guess_num =alist[mid]   # 猜测的数值
+        if guess_num == num:
+            return mid
+        elif guess_num < num:
+            low = mid+1
+        elif guess_num > num:
+            high = mid-1
+    return None
+
+result = binary_search(alist,num)
+print("查找的数是：",num)
+print("ta的索引是",result)    
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