save project

binary_search.py

 # 使用二分查找法，找出9和20在列表里面的索引
 num_list = [1, 3, 5, 8, 11, 15, 17, 18, 20, 21]
-def x(quest):
+def x(alist,quest):
     low=0
-    high=len(num_list)-1
+    high=len(alist)-1
     while True:
         mid=(low+high)//2
-        if num_list[mid]>quest:
+        if alist[mid]>quest:
             high=mid-1
-        elif num_list[mid]==quest:
-            print('找到了,索引是：',num_list[mid])
+        elif alist[mid]==quest:
+            return mid
             break
         elif high<low:
-            print('没找到')
+            return None
             break
         else:
             low=mid+1
-x(4)
\ No newline at end of file
+print(x(num_list,5))
\ No newline at end of file