walmart labs 的catalog组。职位full stack，主要负责api和walmart的catalog内部工具
第一轮，三姐。flatten binary tree to linkedlist (recursion and inplace), time complexity.
what is preorder, inorder, postorder
第二轮（年轻三哥）：
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What is event loop
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Why use redux.
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spring framework ， 多线程熟悉吗
Coding（use react）: design page, search box, table column, search box, search box can select all the column match the key word in search box.
Coding（use redux）: 3 data, customer(firstname last name, ssn, balance ), loans(ssn, balance) , bank(ssn, account), design the action part and reducer part.
第三轮：
coding: str = ‘11122333444’ , each number appear 3 times , only one appear twice , find that number, improve performance
BH：做过的project，难点在哪，聊天。
第四轮：经理面，聊天，聊项目