比特币如何防止双花？

Question

有人可以帮我创建一个伪代码来显示比特币如何防止双花吗？ 这是我的代码（在https://www.sofi.com/ 的帮助下）：

This program is to prevent double-spending:

Person A and Person B go to a store with only one collective BTC to spend.
Person A buys a TV costing exactly 1 BTC.
Person B buys a motorcycle that also costs exactly 1 BTC.
blockchain = []
pool_of_unconfirmed_transactions = []

Both transactions go into a pool of unconfirmed transactions:
pool_of_unconfirmed_transactions.append(person A buys)
pool_of_unconfirmed_transactions.append(person B buys)

only the first transaction gets confirmations
and is verified by miners in the next block.
If person A buys == first buyer:
    person A's transaction == valid
    blockchain.append(person A's transaction)
    del mem_pool[person B's transaction]
else:
    person B's transaction == valid
    del mem_pool[person A's transaction]

Whichever transaction gets the maximum number of network confirmations
(typically a minimum of six) will be included in the blockchain,
 while others are discarded.
Once confirmations and transactions are put on the blockchain
 they are time-stamped, rendering them irreversible and impossible to alter.

没事吧？ 有什么建议吗？

Answer 1

比特币通过不产生一个花费另一个块之前已经花费的 UTXO 的块来防止双重花费。内存池或未确认的事务与它无关。

包含双花的比特币区块不是有效区块，因此世界上所有比特币节点都会拒绝它。这也是它被称为“公共账本”的原因——比特币区块链是整个系统所有余额的账本（账本）。

因此，如果有两个竞争交易，矿工将决定哪个被花费，哪个被拒绝。