blakemerryman · December 22, 2014 19:40 · Dec 22, 2014
diff --git a/gistfile1.txt b/gistfile1.txt
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+#!/usr/bin/env xcrun swift
+
+/*
+/r/DailyProgrammer Challenge # 193
+Reddit - http://www.reddit.com/r/dailyprogrammer/
+Blake Merryman
+Github - https://github.com/blakemerryman
+Challenge Description:
+An international shipping company is trying to figure out how to manufacture various types of containers. Given a volume they want to figure out the dimensions of various shapes that would all hold the same volume.
+Input:
+    * A volume in cubic meters.
+Output:
+    * Dimensions of containers of various types that would hold the volume. 
+    * The following containers are possible.
+        * Cube
+        * Ball (Sphere)
+        * Cylinder
+        * Cone
+Ex:
+    Input:
+        > 27.0
+    Output:
+        > Cube: 3.00m width, 3.00m high, 3.00m tall
+          Cylinder: 3.00m tall, Diameter of 3.38m
+          Sphere: 1.86m Radius
+          Cone: 9.00m tall, 1.69m Radius
+Notes:
+    * Input can be an integer or double value
+    * To run,
+        1. Make executable (chmod +x filename.swift)
+        2. Run by entering the following into the console:
+            > ./filename.swift ###
+                or
+            > ./filename.swift ###.##
+*/
+
+import Cocoa
+
+
+// MARK: - Handle User Input
+
+var volume = 0.0
+
+// Grab input from console
+for argument in Process.arguments {
+
+    let argumentAsDouble = (argument as NSString).doubleValue
+
+    if argumentAsDouble > 0.0 {
+        volume = argumentAsDouble
+    }
+}
+
+// MARK: - Important Constants & Enums
+
+let kDimensionUnits  = "m"
+let kDimensionHeight = "height"
+let kDimensionWidth  = "width"
+let kDimensionDepth  = "depth"
+let kDimensionRadius = "radius"
+
+enum ContainerShape: String {
+    case Cube     = "Cube"
+    case Sphere   = "Sphere"
+    case Cylinder = "Cylinder"
+    case Cone     = "Cone"
+}
+
+
+// MARK: - NumberFormatter
+
+var numberFormatter = NSNumberFormatter()
+
+numberFormatter.maximumSignificantDigits = {
+    var numberOfSigDigs = 0
+    for character in volume.description {
+        if character != "." {
+            numberOfSigDigs++
+        }
+    }
+    return numberOfSigDigs
+}()
+
+// MARK: - Utility Functions
+
+/// Computes the height, width, & depth of a cube for a given volume.
+func computeDimensionsForCubeWithVolume(volume: Double) -> [String:Double] {
+
+    let aSide = cbrt(volume)
+
+    return [kDimensionHeight:aSide, kDimensionWidth: aSide, kDimensionDepth: aSide]
+}
+
+/// Computes the radius of a sphere for a given volume.
+func computeDimensionsForSphereWithVolume(volume: Double) -> [String:Double] {
+
+    let radius = cbrt( ( 3.0 * volume ) / ( 4.0 * M_PI ) )
+
+    return [kDimensionRadius:radius]
+}
+
+/// Computes the height & radius of a cylinder with minimum surface area for given volume.
+func computeDimensionsForCylinderWithVolume(volume: Double) -> [String:Double] {
+
+    /*
+    Note on calculations:
+
+    We know the desired volume of the cylinder but not the desired dimensions.
+    This is an equation with two unknowns and in the Real numbers could have many
+    possible solutions. To narrow it down to one, we are going to use a little
+    calculus to minimize the surface area and thus give us the appropriate
+    radius & height for the given volume.
+
+    User copper.hat gives a great explanation behind getting the correct formulae
+    for the radius and height ( http://math.stackexchange.com/a/584770 ).
+    */
+
+    let radius = cbrt(volume / (2 * M_PI))
+    let height = cbrt((4 * volume) / M_PI)
+
+    return [kDimensionRadius:radius,kDimensionHeight:height]
+}
+
+/// Computes the height & radius of a cone with a slant angle of 45º for given volume.
+func computeDimensionsForConeWithVolume(volume: Double) -> [String:Double] {
+
+    /*
+    Note on calculations:
+
+    We know the desired volume of the cone but not the desired dimensions.
+    This is an equation with two unknowns and in the Real numbers could have many
+    possible solutions. To narrow it down to one, we are going to assume that
+    height and radius are equal, giving us a slant angle of 45º.
+
+    We could make any number of assumptions (desired slant angle, maximum height,
+    maximum radius, etc) but this one was chosen for simplicity.
+
+    V = ( h * pi * r^2 ) / 3 ... but h = r so
+    = ( pi * r^3 ) / 3     ... and solving for r gives us...
+    */
+
+    let radius = cbrt((3 * volume) / M_PI)
+
+    return [kDimensionRadius:radius,kDimensionHeight:radius]
+}
+
+// Given a set of dimensions & shape, properly formats the string for output.
+func formatDimensions(dimensions: [String:Double], forShape shape: ContainerShape) -> String {
+
+    switch shape {
+
+    case .Cube:
+        let height = numberFormatter.stringFromNumber(dimensions[kDimensionHeight]!)!
+        let width  = numberFormatter.stringFromNumber(dimensions[kDimensionWidth]!)!
+        let depth  = numberFormatter.stringFromNumber(dimensions[kDimensionDepth]!)!
+        return "\(shape.rawValue): \(height) \(kDimensionUnits) \(kDimensionHeight), \(width) \(kDimensionUnits) \(kDimensionWidth), \(depth) \(kDimensionUnits) \(kDimensionDepth)"
+
+    case .Cone, .Cylinder:
+        let radius = numberFormatter.stringFromNumber(dimensions[kDimensionRadius]!)!
+        let height = numberFormatter.stringFromNumber(dimensions[kDimensionHeight]!)!
+        return "\(shape.rawValue): \(radius) \(kDimensionUnits) \(kDimensionRadius),\(height) \(kDimensionUnits) \(kDimensionHeight)"
+
+    case .Sphere:
+        let radius = numberFormatter.stringFromNumber(dimensions[kDimensionRadius]!)!
+        return "\(shape.rawValue): \(radius) \(kDimensionUnits) \(kDimensionRadius)"
+    }
+}
+
+// MARK: - Primary Function
+
+/// Function computes possible dimensions for the passed in shape & volume. Computed values are returned in a dictionary.
+func computeDimensions(forShape shape: ContainerShape, withVolume volume: Double) -> String {
+    switch shape {
+    case .Cube:
+        return formatDimensions(computeDimensionsForCubeWithVolume(volume), forShape: .Cube)
+    case .Cone:
+        return formatDimensions(computeDimensionsForConeWithVolume(volume), forShape: .Cone)
+    case .Cylinder:
+        return formatDimensions(computeDimensionsForCylinderWithVolume(volume), forShape: .Cylinder)
+    case .Sphere:
+        return formatDimensions(computeDimensionsForSphereWithVolume(volume), forShape: .Sphere)
+    }
+}
+
+
+// --------------------------------------------------
+// MARK: - Comput & Output to User
+
+println("\n\nContainer Dimensions for a given volume of \(volume) \(kDimensionUnits)^3")
+println("----------------------------------------------------------")
+println("\(computeDimensions(forShape: .Cube, withVolume: volume))")
+println("\(computeDimensions(forShape: .Cone, withVolume: volume))")
+println("\(computeDimensions(forShape: .Cylinder, withVolume: volume))")
+println("\(computeDimensions(forShape: .Sphere, withVolume: volume))")
+println("----------------------------------------------------------\n\n")