Level2 - H - Index(Swift)

func solution(_ citations:[Int]) -> Int {
    
    let sortedCitaions = citations.sorted(by: >)
    var result = 0
    
    for i in 0..<sortedCitaions.count {
        if i < sortedCitaions[i] {
            result += 1
        }
    }
    return result
}