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]
-a=0+len(num_list)-1
+a=(len(num_list)-1)//2
+while(num_list[a]!=20):
+    if num_list[a]<20:
+        a=(a+len(num_list))//2
+    else:
+        a=(a-1)//2
+print(a)
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