An ethereum voting smart contract

Voter.sol

pragma solidity ^0.4.0;
pragma experimental ABIEncoderV2;

contract Voter {
    
    struct OptionPos {
        uint pos;
        bool exists;
    }
    
    uint[] public votes;
    string[] public options;
    mapping(address => bool) hasVoted;
    mapping(string => OptionPos) posOfOption;
    
    constructor(string[] _options) public {
        options = _options;
        votes.length = options.length;
        
        for (uint i = 0; i<options.length; i++) {
            OptionPos memory optionPos = OptionPos(i, true);
            string optionName = options[i];
            posOfOption[optionName] = optionPos;
        }
    }
    
    function vote(uint option) public {
        require(0 <= option && option < options.length, "Invalid option");
        require(!hasVoted[msg.sender], "user has voted previously");
        
        votes[option] = votes[option] + 1;
        hasVoted[msg.sender] = true;
    }
    
    function vote(string optionName) public {
        require(!hasVoted[msg.sender], "user has voted previously");
        
        OptionPos memory optionPos = posOfOption[optionName];
        require(optionPos.exists, "Option does not exists");
        
        votes[optionPos.pos] = votes[optionPos.pos] + 1;
        hasVoted[msg.sender] = true;
        
    }
    
    function getOptions() view public returns (string[]) {
        return options;
    }
    
    function getVotes() view public returns (uint[]) {
        return votes;
    }
}