[프로그래머스][Lv. 1] 실패율 Swift 풀이

https://programmers.co.kr/learn/courses/30/lessons/42889

코딩테스트 연습 - 실패율

풀이는 추후에 차차 올리도록 하겠습니다...

 

 

import Foundation
 
func solution(_ N:Int, _ stages:[Int]) -> [Int] {
    var userCount: Int = stages.count
    var stageCounts: [Int:Int] = [Int:Int]()
    for n in 1...N {
        stageCounts.updateValue(0, forKey: n)
    }
    for stage in stages {
        if stage == N + 1 {
            continue
        }
        stageCounts[stage] = stageCounts[stage]! + 1
    }
    var stageFailrates: [Int:Double] = [Int:Double]()
    for stage in 1...N {
        let stageCount = stageCounts[stage]!
        if userCount != 0 {
            stageFailrates[stage] = Double(stageCount) / Double(userCount)
            userCount -= stageCount            
        } else {
            stageFailrates[stage] = 0
        }
    }
    var answer: [Int] = [Int]()
    let sortedStageFailrates = stageFailrates.sorted { 
        if $0.1 > $1.1 {
            return true
        } else if $0.1 == $1.1 {
            return $0.0 < $1.0
        } else {
            return false
        }
    }
    for i in 0..<sortedStageFailrates.count {
        answer.append(sortedStageFailrates[i].key)
    }
    return answer
}