NFT airdrop, using merkle tree

How it works:

Using merkle tree, we can airdrop tokens without writing their addresses in a smart contract. It is enough to generate a tree on site and write the root hash into the contract. In order for the user to be able to get free nft, he just needs to pass some proofs to the contract, which he has received from the site. No array of addresses is stored in the contract.

Links:

• https://soliditydeveloper.com/merkle-tree
• https://www.youtube.com/watch?v=n6nEPaE7KZ8
• https://medium.com/@ItsCuzzo/using-merkle-trees-for-nft-whitelists-523b58ada3f9