Решение

class Solution {
    fun interpret(command: String): String {
        val n = command.length
        val sb = StringBuilder(n)
        var i = 0
        while (i < n) {
            when (command[i]) {
                'G' -> {
                    sb.append('G')
                    i++
                }
                '(' -> {
                    if (command[i + 1] == ')') {
                        sb.append('o')
                        i += 2
                    } else {
                        sb.append('a')
                        sb.append('l')
                        i += 4
                    }
                }
                else -> i++
            }
        }
        return sb.toString()
    }
}