93 lines
2.1 KiB
Swift
93 lines
2.1 KiB
Swift
import Foundation
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class Directory {
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var parent: Directory? = nil
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var children: [String: Directory] = [:]
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var size: Int = 0
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init(parent: Directory? = nil) {
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self.parent = parent
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}
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func child(_ name: String) -> Directory {
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if let child = children[name] {
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return child
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}
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let new = Directory(parent: self)
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children[name] = new
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return new
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}
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func totalSize() -> Int {
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return size + children.values.reduce(0) { $0 + $1.totalSize() }
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}
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func all(_ callback: (Directory) -> Void) {
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callback(self)
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for child in children.values {
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child.all(callback)
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}
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}
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}
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let input = try String(contentsOf: URL(fileURLWithPath: "day7.input"))
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let scanner = Scanner(string: input)
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let root = Directory()
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var current: Directory? = nil
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while !scanner.isAtEnd {
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guard scanner.scanString("$") != nil else {
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fatalError("Expected $")
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}
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if scanner.scanString("cd") != nil, let dir = scanner.scanUpToString("\n") {
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switch dir {
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case "/":
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current = root
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case "..":
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current = current!.parent
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default:
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current = current!.child(dir)
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}
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} else if scanner.scanString("ls") != nil {
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while true {
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if let size = scanner.scanInt() {
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current!.size += size
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} else if scanner.scanString("dir") != nil {
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} else {
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break
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}
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_ = scanner.scanUpToString("\n");
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}
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}
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}
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var sum = 0
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root.all {
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let size = $0.totalSize()
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if size < 100000 {
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sum += size
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}
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}
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print("Part 1: Sum of size of all directories < 100000:", sum)
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let diskSize = 70000000
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let freeSpace = diskSize - root.totalSize()
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let requiredSize = 30000000
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let toFree = requiredSize - freeSpace
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var smallest = Int.max
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root.all {
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let size = $0.totalSize()
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if size >= toFree && size < smallest {
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smallest = size
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}
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}
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print("Part 2: Smallest folder to delete:", smallest)
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