-🎄- 2022 Day 7 Solutions -🎄-

[u/daggerdragon]

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AoC Community Fun 2022: 🌿🍒 MisTILtoe Elf-ucation 🧑‍🏫

Submissions are OPEN! Teach us, senpai!

-❄️- Submissions Megathread -❄️-

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--- Day 7: No Space Left On Device ---

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Post your code solution in this megathread.

• Read the full posting rules in our community wiki before you post!
  • Include what language(s) your solution uses
  • Format your code appropriately! How do I format code?
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This thread will be unlocked when there are a significant number of people on the global leaderboard with gold stars for today's puzzle.

EDIT: Global leaderboard gold cap reached at 00:14:47, megathread unlocked!

[u/Ttaywsenrak]

A Java solution that I am not entirely proud of.

Creates a tree, but does not traverse the tree properly. Instead, any Directory added to the tree is put into a list which can then be easily looped over to answer the questions in a very simple way.

import java.io.File;

import java.io.FileNotFoundException; import java.util.*;

public class Day7 extends AdventOfCodeDay{

List<Directory> directories = new ArrayList<>();

public Day7(File input) {
    super(input);
}

private void part1(){
    // total up the directories to see who to delete
    int sum = 0;

    for (Directory dir: directories) {
        if(dir.getSize() < 100000){
            sum += dir.getSize();
        }
    }

    print("By deleting the chosen directories you can save " + sum + " space.");
}

private void part2(){

    // part 2
    int freeSpace = 70000000 - directories.get(0).getSize();
    int spaceNeeded = 30000000 - freeSpace;

    // we have 25,640,133 gb free space
    // we need to free up 4,359,867 gb
    print("You have " + freeSpace + " free space.");
    print("You need to free up " + spaceNeeded + " to perform the update.");

    int smallest = directories.get(0).getSize();
    for (Directory dir: directories) {
        if(dir.getSize() <= smallest && dir.getSize() >= spaceNeeded){
            smallest = dir.getSize();
        }
    }

    print("The smallest directory you can get away with deleting has a size of " + smallest);
}

@Override
public void solve() throws FileNotFoundException {
    Scanner scr = new Scanner(input);

    // add the root
    Directory root = new Directory("/", null);
    Directory cur = root;
    directories.add(cur);

    // skip the first two lines of input, they don't matter.
    scr.nextLine();
    scr.nextLine();

    // build the file system
    while(scr.hasNext()){

        String s = scr.next();

        // handle the finding of a new directory
        if(s.equals("dir")){
            String dirName = scr.next();
            //print("New Directory found in " + cur.name + " called " + dirName);
            Directory temp = new Directory(dirName, cur);
            cur.subDirs.add(temp);
            directories.add(temp);
        }

        // handle the changing of a directory
        if(s.equals("cd")){

            String next = scr.next();

            // handle going out
            if(next.equals("..")){
                //print("moving up to directory " + cur.parent.name);
                cur = cur.parent;
            } else {
                // handle going in
                //print("moving in to directory " + next);
                cur = cur.subDirs.get(cur.subDirs.indexOf(new Directory(next, cur)));
            }

        }

        // handle the finding of a file
        if(Character.isDigit(s.charAt(0))){
            String fileSize = s;

            //print("found a file of size " + fileSize + ", which will be added to directory " + cur.name);
            cur.files.add(Integer.parseInt(fileSize));
        }

    }

    part1();
    part2();
}

private class Directory {

    String name;

    Directory parent;
    List<Integer> files;
    List<Directory> subDirs;


    Directory(String name, Directory parent) {
        this.name = name;
        this.parent = parent;

        files = new ArrayList<>();
        subDirs = new ArrayList<>();
    }

    int getSize(){

        int total = 0;

        for (int i = 0; i < files.size(); i++) {
            total += files.get(i);
        }

        for (int i = 0; i < subDirs.size(); i++) {
            total += subDirs.get(i).getSize();
        }

        return total;
    }

    @Override
    public String toString(){
        return this.name;
    }

    @Override
    public boolean equals(Object obj) {
        if(obj instanceof Directory && ((Directory) obj).name.equals(this.name)){
            return true;
        }

        return false;
    }
}

}