Would this pseudo random algorithm be failproof:
I'm implementing a lottery contract and the winner is chose by getting addresses of each player who joined , packing the addresses into a string and hashing that value, casting it to an uint, and getting an index for an array out of it. I am thinking even if someone reads all the addresses and estimates the winners, it wouldn't be 100% accurate, because it depends whether another account will join or not.
edit: after choosing one winner, the players array gets scrambled in front-end and set again by the contract admin.