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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, 21,999]
-x = 999
+x = 99
 
 low = 0
 high = len(num_list) -1