AdventOfCode.com 2016/Day 3 Solution (http://adventofcode.com/2016/day/3) (Part 1)

Day3Part1.playground.swift

import Foundation

struct Triangle {
    let vertices: [Int]
    
    init?(vertices:[Int]) {
        guard vertices.count == 3 else { return nil }
        
        guard vertices[0] + vertices[1] > vertices[2],
            vertices[0] + vertices[2] > vertices[1],
            vertices[2] + vertices[1] > vertices[0] else {
                return nil
        }
        
        self.vertices = vertices
    }
}

// Day 3:
let testInput = "  330  143  338"

let filePath = Bundle.main.path(forResource: "Day3", ofType: "txt")
let inputData = FileManager.default.contents(atPath: filePath!)

if let input = String(data: inputData!, encoding: .utf8) {
    // Split each line into a string that might represent an array of vertices
    let triangleStrings = input.components(separatedBy: "\n")
    
    let triangles = triangleStrings.map { (vertexString) -> [Int] in                    // For each line in the input file...
        return vertexString.components(separatedBy: CharacterSet(charactersIn: " "))    // Split the string into strings by spaces...
            .flatMap({ return Int($0) })                                                // Convert those strings to Ints...
        }
        .flatMap({ return Triangle(vertices:$0) })                                      // Convert those Ints to Triangles
    
    
    print("\(triangles.count)")
}

This one used a resource text file as input.