I have a question about how to figure out balance of specific address in the Bitcoin.
There are many node in the blockchain(total # of nodes are 10000 based on 01/16/2019). but some nodes may have broken chain because they want to spend time to mining the new block rather than verification the mined blocks.
So here, I am wondering that how to check the balance of specific address when end-user query to the blockchain. If the node that has broken chain receive the query, the response is also not correct. but if the node that has clear chain receive the query, the response will be correct. But Blockchain has no function that can provide some data from blockchain. So the website such as Ehterscan.io, BlockExplorer have seeded a full node in the blockchain and the node has clear chain because the node's purpose is to provide clear data, not mining the new block to get reward.
This is my assumption. how to think about it?
Sorry for my English.