Question

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

Answer 1

object LongestRepeatingSubstring {

  // Function to find the longest common prefix between two strings
  def longestCommonPrefix(sub1: String, sub2: String): String = {
    val minLen = math.min(sub1.length, sub2.length)

    for (i <- 0 until minLen) {
      if (sub1(i) != sub2(i)) {
        return sub1.substring(0, i)
      }
    }

    sub1.substring(0, minLen)
  }

  // Function to find the longest repeating substring
  def longestRepeatingSubstring(s: String): String = {
    var lrs = ""
    val size = s.length

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

    lrs
  }

  def main(args: Array[String]): Unit = {
    val s = "javascriptpythonphpjavacdartcppjavacsharpscala"
    
    println(longestRepeatingSubstring(s))
  }
}



/*
run:

pjavac

*/

 

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