LeetCode/kt/longest-common-prefix.kt

class Solution {
    private fun findCommonPrefix(
        x: String,
        y: String,
    ): String =
        minOf(x.length, y.length).let { maxLength ->
            (0..maxLength - 1).takeWhile { i ->
                x[i] == y[i]
            }.lastOrNull() ?: -1
        }.let { maxIndex ->
            x.substring(0, maxIndex + 1)
        }

    fun longestCommonPrefix(strs: Array<String>): String =
        strs.drop(1).fold(strs[0]) { commonPrefix, str ->
            findCommonPrefix(commonPrefix, str)
        }
}