Day 0:weightMean

Day 0:weightMean

import Foundation
//Day 0:weightMean
func weightMean(numbers: [Int] , weights : [Int]) -> Double {
    var sum = 0.0
    var totalWeights = 0
    for i in 0..<numbers.count {
        sum += Double(numbers[i] * weights[i])
        totalWeights += weights[i]
    }
    let weightMean = sum / Double(totalWeights)
    return weightMean
}


//let number = Int(readLine(strippingNewline: true)!)!
//let arrValue = readLine(strippingNewline: true)!.characters
//    .split {$0 == " "}
//    .map (Int.init)
//print(mean(numbers: arrValue))
//print(median(numbers: arrValue))
//print(mode(numbers: arrValue))
//let arrValue = [1,1,1,2,2,2,3,3]
//print(mode(numbers: arrValue))
//weightMean(numbers: [10, 40, 30, 50, 20], weights : [1, 2, 3, 4, 5])

let stdout = ProcessInfo.processInfo.environment["OUTPUT_PATH"]!
FileManager.default.createFile(atPath: stdout, contents: nil, attributes: nil)
let fileHandle = FileHandle(forWritingAtPath: stdout)!

guard let n = Int((readLine()?.trimmingCharacters(in: .whitespacesAndNewlines))!)
    else { fatalError("Bad input") }

guard let arTemp = readLine() else { fatalError("Bad input") }
let ar: [Int] = arTemp.split(separator: " ").map {
    if let arItem = Int($0.trimmingCharacters(in: .whitespacesAndNewlines)) {
        return arItem
    } else { fatalError("Bad input") }
}

guard let arTemp2 = readLine() else { fatalError("Bad input") }
let ar2: [Int] = arTemp2.split(separator: " ").map {
    if let arItem = Int($0.trimmingCharacters(in: .whitespacesAndNewlines)) {
        return arItem
    } else { fatalError("Bad input") }
}

guard ar.count == n else { fatalError("Bad input") }
let resultvalue = weightMean(numbers: ar, weights : ar2)
let result = String(format: "%.1f", resultvalue)

fileHandle.write(String(result).data(using: .utf8)!)
fileHandle.write("\n".data(using: .utf8)!)