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# orkoden/demotask.swift Last active Apr 23, 2019

swift solution to codility demo task
 // MissingInteger // Find the smallest positive integer that does not occur in a given sequence. //This is a demo task. // //Write a function: // //public func solution(_ A : inout [Int]) -> Int // //that, given an array A of N integers, returns the smallest positive integer (greater than 0) that does not occur in A. // //For example, given A = [1, 3, 6, 4, 1, 2], the function should return 5. // //Given A = [1, 2, 3], the function should return 4. // //Given A = [−1, −3], the function should return 1. // //Write an efficient algorithm for the following assumptions: // //N is an integer within the range [1..100,000]; //each element of array A is an integer within the range [−1,000,000..1,000,000]. // let A = [1, 3, 6, 4, 1, 2] let A2 = [1, 2, 3] let A3 = [-1, -3] public func solution(_ a : [Int]) -> Int { let noNegative = a.filter { \$0 > 0 } let uniqueNumbers = Set(noNegative) var uniqueArray = Array(uniqueNumbers) uniqueArray.sort() for (index, number) in uniqueArray.enumerated() { if number > index + 1 { return index + 1 } } let largestIntNotPresent = (uniqueArray.last ?? 0) + 1 return largestIntNotPresent } let a = solution(A) let a2 = solution(A2) let a3 = solution(A3)
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