Question

How to find the longest repeating substring in a string with Kotlin

Answer 1

fun longestCommonPrefix(sub1: String, sub2: String): String {
    val minLen = minOf(sub1.length, sub2.length)

    for (i in 0 until minLen) {
        if (sub1[i] != sub2[i]) {
            return sub1.substring(0, i)
        }
    }

    return sub1.substring(0, minLen)
}

fun longestRepeatingSubstring(s: String): String {
    var lrs = ""
    val size = s.length

    for (i in 0 until size) {
        for (j in i + 1 until size) {
            val lcp = longestCommonPrefix(s.substring(i), s.substring(j))
            if (lcp.length > lrs.length) {
                lrs = lcp
            }
        }
    }

    return lrs
}

fun main() {
    val s = "javascriptpythonphpjavacdartcppjavacsharpkotlin"
    
    println(longestRepeatingSubstring(s))
}



/*
run:

pjavac

*/

 

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