find the kth least common element in an array in swift

main.swift
func kthLeastCommonElement(in array: [Int], k: Int) -> Int? {
    // Count the frequency of each element in the array
    var frequency = [Int: Int]()
    for element in array {
        frequency[element, default: 0] += 1
    }
    
    // Sort the elements by increasing frequency
    let sortedElements = array.sorted { frequency[$0]! < frequency[$1]! }
    
    // Find the kth least common element
    var count = 0
    var currentElement: Int?
    for element in sortedElements {
        if element != currentElement {
            count += 1
            currentElement = element
        }
        if count == k {
            return element
        }
    }
    
    // If there are less than k distinct elements in the array, return nil
    return nil
}
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