g0001_0100.s0038_count_and_say.Solution.kt Maven / Gradle / Ivy

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package g0001_0100.s0038_count_and_say

// #Medium #Top_Interview_Questions #String #2022_09_18_Time_317_ms_(41.11%)_Space_35.3_MB_(85.56%)

class Solution {
    fun countAndSay(n: Int): String {
        if (n == 1) {
            return "1"
        }
        val res = StringBuilder()
        val prev = countAndSay(n - 1)
        var count = 1
        for (i in 1 until prev.length) {
            if (prev[i] == prev[i - 1]) {
                count++
            } else {
                res.append(count).append(prev[i - 1])
                count = 1
            }
        }
        res.append(count).append(prev[prev.length - 1])
        return res.toString()
    }
}