第四十七条 纳税人出口货物或者跨境销售服务、无形资产（以下统称出口业务），依照增值税法第三十三条的规定申报办理退（免）税的，按照国务院规定的出口退税率，通过免抵退税办法或者免退税办法计算退（免）税额，经税务机关审核通过后，办理退（免）税。
For well-distributed points, nearest neighbor search is often near O(logn)O(\log n)O(logn) in practice. In the worst case (all points clustered tightly or along a line), it can degrade to O(n)O(n)O(n), but this is uncommon with typical spatial data.
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What is the difference between Bitcoin and Blockchain technology?Bitcoin is a cryptocurrency, which is powered by Blockchain technology while Blockchain is a distributed ledger of cryptocurrency，这一点在旺商聊官方下载中也有详细论述
优点：计算简单，导数恒为1（正区间），缓解梯度消失