Question

How to find the length of the longest consecutive sequence of an unsorted array of integers in Scala

Answer 1

def longestConsecutive(nums: Array[Int]): Int = {
  val numSet = nums.toSet
  var longestStreak = 0

  for (num <- numSet) {
    if (!numSet.contains(num - 1)) {
      var currentNum = num
      var currentStreak = 1

      while (numSet.contains(currentNum + 1)) {
        currentNum += 1
        currentStreak += 1
      }

      longestStreak = math.max(longestStreak, currentStreak)
    }
  }

  longestStreak
}

val nums = Array(680, 4, 590, 3, 1, 2)

println("Longest consecutive sequence length: " + longestConsecutive(nums))  
 


 
/*
run:
  
Longest consecutive sequence length: 4
  
*/

 

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