save project

my_search.py

@@ -4,6 +4,23 @@ alist = []
 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
+# 请完善二分查找函数binary_search(),查找出num在列表alist里面的索引
 
 def binary_search(alist,num):
+    low = 0
+    high = len(alist)-1
+    while  low <=high:
+        mid  = (low+high) // 2
+        guess = alist[mid]
+        if guess  == num:
+            print('找到了','它的索引是',mid)
+            break
+        elif  guess < num:
+            low = mid+1
+        else:
+            high = mid-1
+    return  None
+
+result = binary_search(alist,num)
+print('老师给的数是:',num)
+print('它在列表里的索引是；',result)
\ No newline at end of file