[プログラマー]コードテスト練習-21

function solution(numbers, hand) {
    var answer = '';
    var left = 10;
    var right = 12;
    
    numbers.forEach((n) => {
        if (n % 3 == 1) {
            answer += 'L';
            left = n;
        } else if (n != 0 && n % 3 == 0) {
            answer += 'R';
            right = n;
        } else {
            if (n == 0) n = 11;
            var lLen = left % 3 == 1 ? Math.abs(left - (n - 1)) / 3 + 1 : Math.abs(left - n) / 3;
            var rLen = right % 3 == 0 ? Math.abs(right - (n + 1)) / 3 + 1 : Math.abs(right - n) / 3;
            if (lLen < rLen || ((lLen == rLen) && hand == "left")) {
                answer += 'L';
                left = n;
            } else if (lLen > rLen || ((lLen == rLen) && hand == "right")) {
                answer += 'R';
                right = n;
            }
        }
    })
    
    return answer;
}