Brackets.kt

package ru.fbear.strings

class Brackets {

    fun valid(bracketsString: String): Boolean {
        var left = 0
        var right = 0

        for (sym in bracketsString) {
            when (sym) {
                '(' -> left++
                ')' -> right++
            }

            if (right > left) return false

        }

        return left == right
    }
}