You need to compile those addresses then give them a number. Then use bitcoin block to decide the winner.
Example last two hash digit of block : https://www.blockchain.com/explorer/blocks/btc/773373
Result: 00000000000000000002f4a304f5939bc22e379a208b2b977fd84021d8cb59e2
Winner: 92
To expand on this to help you with compiling the list Rbah, here are the first 3 participants compiled in a format that you can use continue on to do the whole list of entrants.
[10] TheChin0s bc1qnn44lgfzmzl3kk68gccdke4z6vxgwju272nsss
[11] GazetaBitcoin bc1qgfluvq03jcqzvaz6dc00qqgvyvmfuxra6etsd2
[12] CoinEraser bc1q4v2e08evleg047rcfnea97rampclqqzp682pgg
[11] GazetaBitcoin [url=https://bitcointalksearch.org/topic/50-in-btc-giveaway-5435424]bc1qgfluvq03jcqzvaz6dc00qqgvyvmfuxra6etsd2[/url]
[12] CoinEraser [url=https://bitcointalksearch.org/topic/m.61609650]bc1q4v2e08evleg047rcfnea97rampclqqzp682pgg[/url]
If you're wondering how xLays got 92:
00000000000000000002f4a304f5939bc22e379a208b2b977fd84021d8cb59e2 is the winning hash. 9e2 are the last parts of the hash. Remove the "e" and you get 92.
The reason for the list starting at [10], is if the result the hash is 9e2 like above and you've started counting entrants between 1 and 10, the winner is both [2] and [92]. Starting at 10 should stop you from facing that problem.