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contracts...RockPaperScissors.sol

// SPDX-License-Identifier: GPL-3.0

pragma solidity ^0.8;

contract RockPaperScissors {
    
    uint public enrollmentAmount;
    address owner;
    address[] public players;
    mapping(address => bool) playerPlayed;
    mapping(address => bytes32) public choices;
    
    bytes32 ROCK = keccak256(bytes("Rock"));
    bytes32 PAPER = keccak256(bytes("Paper"));
    bytes32 SCISSOR = keccak256(bytes("Scissor"));
    
    // pass enrollment amount in wei
    constructor() {
        owner = msg.sender;
    }
    
    receive() external payable{}
    
    function initialiseGame(uint256 enrollmentAmount, address player1, address player2) public {
        require(msg.sender == owner);
        require(player1 != player2);
        enrollmentAmount = enrollmentAmount;
        players.push(player1);
        players.push(player2);
        playerPlayed[player1] = false;
        playerPlayed[player2] = false;
    }
    
    function playGame(string memory choice) public payable {
        require(msg.value == enrollmentAmount);
        require(msg.sender == players[0] || msg.sender == players[1]);
        
        choices[msg.sender] = keccak256(bytes(choice));
        playerPlayed[msg.sender] = true;
    }
    
    function _resetGame() internal {
        delete choices[players[0]];
        delete choices[players[1]];
        delete playerPlayed[players[0]];
        delete playerPlayed[players[0]];
        delete players;
    }
    
    function endGameAndDistributeReward() public {
        require(msg.sender == owner);
        require(playerPlayed[players[0]] && playerPlayed[players[1]]);
        
        address winner;
        
        if (choices[players[0]] == ROCK && choices[players[1]] == SCISSOR) {
            winner = players[0];
        } else if (choices[players[0]] == ROCK && choices[players[1]] == PAPER) {
            winner = players[1];
        } else if (choices[players[0]] == PAPER && choices[players[1]] == ROCK) {
            winner = players[0];
        } else if (choices[players[0]] == PAPER && choices[players[1]] == SCISSOR) {
            winner = players[1];
        } else if (choices[players[0]] == SCISSOR && choices[players[1]] == PAPER) {
            winner = players[0];
        } else if (choices[players[0]] == SCISSOR && choices[players[1]] == ROCK) {
            winner = players[1];
        }
        
        _resetGame();
        
        payable(winner).transfer(address(this).balance);
    }
}