// SPDX-License-Identifier: UNLICENSED
pragma solidity =0.6.11;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/cryptography/MerkleProof.sol";
import "./interfaces/IMerkleDistributor.sol";

contract MerkleDistributor is IMerkleDistributor {
    address public immutable override token;
    bytes32 public immutable override merkleRoot;

    // This is a packed array of booleans.
    mapping(uint256 => uint256) private claimedBitMap;

    constructor(address token_, bytes32 merkleRoot_) public {
        token = token_;
        merkleRoot = merkleRoot_;
    }

    function isClaimed(uint256 index) public view override returns (bool) {
        uint256 claimedWordIndex = index / 256;
        uint256 claimedBitIndex = index % 256;
        uint256 claimedWord = claimedBitMap[claimedWordIndex];
        uint256 mask = (1 << claimedBitIndex);
        return claimedWord & mask == mask;
    }

    function _setClaimed(uint256 index) private {
        uint256 claimedWordIndex = index / 256;
        uint256 claimedBitIndex = index % 256;
        claimedBitMap[claimedWordIndex] = claimedBitMap[claimedWordIndex] | (1 << claimedBitIndex);
    }

    function claim(uint256 index, address account, uint256 amount, bytes32[] calldata merkleProof) external override {
        require(!isClaimed(index), 'MerkleDistributor: Drop already claimed.');

        // Verify the merkle proof.
        bytes32 node = keccak256(abi.encodePacked(index, account, amount));
        require(MerkleProof.verify(merkleProof, merkleRoot, node), 'MerkleDistributor: Invalid proof.');

        // Mark it claimed and send the token.
        _setClaimed(index);
        require(IERC20(token).transfer(account, amount), 'MerkleDistributor: Transfer failed.');

        emit Claimed(index, account, amount);
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

/**
 * @dev These functions deal with verification of Merkle trees (hash trees),
 */
library MerkleProof {
    /**
     * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
     * defined by `root`. For this, a `proof` must be provided, containing
     * sibling hashes on the branch from the leaf to the root of the tree. Each
     * pair of leaves and each pair of pre-images are assumed to be sorted.
     */
    function verify(bytes32[] memory proof, bytes32 root, bytes32 leaf) internal pure returns (bool) {
        bytes32 computedHash = leaf;

        for (uint256 i = 0; i < proof.length; i++) {
            bytes32 proofElement = proof[i];

            if (computedHash <= proofElement) {
                // Hash(current computed hash + current element of the proof)
                computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
            } else {
                // Hash(current element of the proof + current computed hash)
                computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
            }
        }

        // Check if the computed hash (root) is equal to the provided root
        return computedHash == root;
    }
}

// SPDX-License-Identifier: UNLICENSED
pragma solidity >=0.5.0;

// Allows anyone to claim a token if they exist in a merkle root.
interface IMerkleDistributor {
    // Returns the address of the token distributed by this contract.
    function token() external view returns (address);
    // Returns the merkle root of the merkle tree containing account balances available to claim.
    function merkleRoot() external view returns (bytes32);
    // Returns true if the index has been marked claimed.
    function isClaimed(uint256 index) external view returns (bool);
    // Claim the given amount of the token to the given address. Reverts if the inputs are invalid.
    function claim(uint256 index, address account, uint256 amount, bytes32[] calldata merkleProof) external;

    // This event is triggered whenever a call to #claim succeeds.
    event Claimed(uint256 index, address account, uint256 amount);
}

{
  "evmVersion": "istanbul",
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "outputSelection": {
    "*": {
      "*": [
        "evm.bytecode",
        "evm.deployedBytecode",
        "devdoc",
        "userdoc",
        "metadata",
        "abi"
      ]
    }
  },
  "libraries": {}
}

• No Contract Security Audit Submitted- Submit Audit Here

[{"inputs":[{"internalType":"address","name":"token_","type":"address"},{"internalType":"bytes32","name":"merkleRoot_","type":"bytes32"}],"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"uint256","name":"index","type":"uint256"},{"indexed":false,"internalType":"address","name":"account","type":"address"},{"indexed":false,"internalType":"uint256","name":"amount","type":"uint256"}],"name":"Claimed","type":"event"},{"inputs":[{"internalType":"uint256","name":"index","type":"uint256"},{"internalType":"address","name":"account","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"},{"internalType":"bytes32[]","name":"merkleProof","type":"bytes32[]"}],"name":"claim","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"uint256","name":"index","type":"uint256"}],"name":"isClaimed","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"merkleRoot","outputs":[{"internalType":"bytes32","name":"","type":"bytes32"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"token","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"}]

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