Add code for Day 8

Day 8: Memory Maneuver

Sources/AOC2018/day08.swift

@@ -0,0 +1,169 @@
+//
+// Advent of Code 2018 "Day 8: Memory Maneuver"
+//
+
+import Foundation
+
+struct Header {
+    var nChildren = 0
+    var nMeta = 0
+}
+
+struct Node {
+    var header = Header(nChildren: 0, nMeta: 0)
+    var children: [Node] = []
+    var meta: [Int] = []
+    var length = 2      // Smallest node is only a header with no children or meta data
+}
+
+class Maneuver {
+    var treeData: [Int] = []
+    var sumMeta = 0
+
+    // Supply filename for input ex: '/home/peterr/AOC2018/Sources/AOC2018/data/day08.txt'
+    init(withFile filename: String) {
+        let tree = Tools.readFile(fromPath: filename)
+        let chars = tree.components(separatedBy: " ")
+        for char in chars {
+            treeData.append(Int(char) ?? -1)
+        }
+    }
+
+    // Supply test data in the form of a String
+    init(withString tree: String) {
+        let chars = tree.components(separatedBy: " ")
+        for char in chars {
+            treeData.append(Int(char) ?? -1)
+        }
+    }
+
+    // get length of node and sum th meta data for Part 1 as a by-product
+    func getLength(ofChild childData: ArraySlice<Int>) -> Int {
+        let nChildren = childData[childData.startIndex]
+        let nMetaIndex = childData.index(after: childData.startIndex)
+        let nMeta = childData[nMetaIndex]
+        var length = 2
+
+        if nChildren == 0 {
+            let start = childData.startIndex + 2
+            let metaData = Array(childData[start..<start+nMeta])
+            for meta in metaData {
+                sumMeta += meta
+            }
+            return length + nMeta
+        } else {
+            var childIndex = nMetaIndex + 1
+            for _ in 0..<nChildren {
+                let childLength = getLength(ofChild: childData[childIndex...])
+                childIndex += childLength
+                length += childLength
+            }
+            let metaData = Array(childData[childIndex..<childIndex+nMeta])
+            for meta in metaData {
+                sumMeta += meta
+            }
+            length += nMeta
+        }
+        return length
+    }
+
+    func getNode(withChild childData: ArraySlice<Int>) -> Node {
+        let nChildren = childData[childData.startIndex]
+        let nMetaIndex = childData.index(after: childData.startIndex)
+        let nMeta = childData[nMetaIndex]
+        var metaData: [Int] = []
+        let children: [Node] = []
+        var retVal = Node(header: Header(nChildren: nChildren, nMeta: nMeta), children: children, meta: metaData, length: 2)
+
+        if nChildren == 0 {
+            let start = childData.startIndex + 2
+            metaData = Array(childData[start..<start+nMeta])
+        } else {
+            var childIndex = nMetaIndex + 1
+            for _ in 0..<nChildren {
+                let childLength = getLength(ofChild: childData[childIndex...])
+                retVal.children.append(getNode(withChild: childData[childIndex...]))
+                childIndex += childLength
+                retVal.length += childLength
+            }
+            metaData = Array(childData[childIndex..<childIndex+nMeta])
+        }
+        retVal.meta = metaData
+        retVal.length += nMeta
+        return retVal
+    }
+
+    func getValue(forNode node: Node) -> Int {
+        var retVal = 0
+        if (node.header.nChildren == 0) {
+            for meta in node.meta {
+                retVal += meta
+            }
+        } else {
+            for meta in node.meta {
+                let childIndex = meta - 1
+                if (0..<node.children.count).contains(childIndex) {
+                    let childNode = node.children[childIndex]
+                    retVal += getValue(forNode: childNode)
+                }
+            }
+        }
+        return retVal
+    }
+}
+
+class Day08: AOCDay {
+    lazy var tests: (() -> ()) = day08Tests
+    lazy var final: (() -> ()) = day08Final
+
+    let testData = "2 3 0 3 10 11 12 1 1 0 1 99 2 1 1 2"
+    //              0 1 2 3  4  5  6 7 8 9 0  1 2 3 4 5
+    //              A----------------16----------------
+    //                  B-----5----- C-----6-----
+    //                                   D-3---
+    
+    func testManeuverInit() {
+        var maneu = Maneuver(withString: testData)
+        XCTAssertEqual(test: "testManeuverInit string", withExpression: (maneu.treeData[3] == 3))
+        maneu = Maneuver(withFile: "/home/peterr/AOC2018/Sources/AOC2018/data/day08.txt")
+        XCTAssertEqual(test: "testManeuverInit file [3]", withExpression: (maneu.treeData[3] == 2))
+        XCTAssertEqual(test: "testManeuverInit file last", withExpression: (maneu.treeData.last! == 1))
+    }
+
+    func testGetLength() {
+        let maneu = Maneuver(withString: testData)
+        let totalLen = maneu.getLength(ofChild: maneu.treeData[0...])
+        XCTAssertEqual(test: "testGetLength", withExpression: (totalLen == 16))
+        XCTAssertEqual(test: "testGetLength sum Meta", withExpression: (maneu.sumMeta == 138))
+    }
+
+    func testGetNode() {
+        let maneu = Maneuver(withString: testData)
+        let node = maneu.getNode(withChild: maneu.treeData[0...])
+        XCTAssertEqual(test: "testGetNode", withExpression: (node.length == 16))
+    }
+
+    func testGetValue() {
+        let maneu = Maneuver(withString: testData)
+        let node = maneu.getNode(withChild: maneu.treeData[0...])
+        let value = maneu.getValue(forNode: node)
+        XCTAssertEqual(test: "testGetValue", withExpression: (value == 66))
+    }
+
+    func day08Tests() {
+        testManeuverInit()
+        testGetLength()
+        testGetNode()
+        testGetValue()
+    }
+
+    func day08Final() {
+        var maneu = Maneuver(withFile: "/home/peterr/AOC2018/Sources/AOC2018/data/day08.txt")
+        _ = maneu.getLength(ofChild: maneu.treeData[0...])
+        print("Answer to part 1 is: \(maneu.sumMeta)")
+        maneu = Maneuver(withFile: "/home/peterr/AOC2018/Sources/AOC2018/data/day08.txt")
+        let node = maneu.getNode(withChild: maneu.treeData[0...])
+        let value = maneu.getValue(forNode: node)
+        print("Answer to part 2 is: \(value)")
+    }
+}

Sources/AOC2018/main.swift

@@ -19,6 +19,7 @@ allTests.append(Day04().tests)
 allTests.append(Day05().tests)
 allTests.append(Day06().tests)
 allTests.append(Day07().tests)
+allTests.append(Day08().tests)
 
 // Compile list of Answers
 allFinal.append(Day01().final)
@@ -28,6 +29,7 @@ allFinal.append(Day04().final)
 allFinal.append(Day05().final)
 allFinal.append(Day06().final)
 allFinal.append(Day07().final)
+allFinal.append(Day08().final)
 
 if onlyOneDay > 0 {
     print("\nDay \(onlyOneDay)")