Big update: Adding all advent of codes to same repo

AdventOfCode2020/day14/day14.java

@@ -0,0 +1,136 @@
+import java.io.File;
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Scanner;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+class day14 {
+    
+    public static void main(String[] args) {
+        
+        try {
+            
+            File inputFile = new File("input.txt");
+            Scanner in = new Scanner(inputFile);
+            
+            HashMap<Long, Long> memory = new HashMap<>();
+            String mask = "";
+            
+            while (in.hasNext()) {
+                
+                String[] line = in.nextLine().split(" = ");
+                if (line[0].equals("mask")) {
+                    mask = line[1];
+                    System.out.println("Mask: " + mask);
+                } else {
+                    int address = Integer.parseInt(line[0].substring(line[0].indexOf("[") + 1, line[0].indexOf("]")));
+                    long value = Long.parseLong(line[1]);
+                    //memory.put(address, maskedValue(mask, value));
+                    long[] addresses = maskedAddresses(mask, address);
+                    for (long a : addresses) {
+                        System.out.printf("Address: %d | Value: %d \n", a, value);
+                        memory.put(a, value);
+                    }
+                }
+                
+            }
+            
+            long sumLong = 0;
+            
+            for (long key : memory.keySet()) {
+                sumLong += memory.get(key);
+            }
+            
+            System.out.println("Answer: " + sumLong);
+            
+        } catch (Exception e) {
+            System.out.println(e);
+        }
+        
+    }
+    
+    static long maskedValue(String mask, int value) {
+        
+        String binaryString = Integer.toBinaryString(value);
+        
+        while (binaryString.length() != 36) binaryString = "0" + binaryString;
+        
+        String returnString = new String();
+        System.out.println("Binary String: " + binaryString);
+        for (int i = binaryString.length() - 1; i >= 0; i--) {
+            
+            if (binaryString.charAt(i) != mask.charAt(i) && mask.charAt(i) != 'X') {
+                returnString = mask.charAt(i) + returnString;
+            } else {
+                returnString = binaryString.charAt(i) + returnString;
+            }
+            
+        }
+        
+        System.out.println("Return String: " + returnString);
+        
+        return toDenary(returnString);
+        
+    }
+    
+    static long[] maskedAddresses(String mask, int value) {
+        String binaryString = Integer.toBinaryString(value);
+        
+        while (binaryString.length() != 36) binaryString = "0" + binaryString;
+        
+        String returnString = new String();
+        ArrayList<Integer> xlist = new ArrayList<>();
+        System.out.println("Binary String: " + binaryString);
+        for (int i = binaryString.length() - 1; i >= 0; i--) {
+            
+            if (mask.charAt(i) == 'X') xlist.add(i);
+            
+            if (binaryString.charAt(i) != mask.charAt(i) && mask.charAt(i) != '0') {
+                returnString = mask.charAt(i) + returnString;
+            } else {
+                returnString = binaryString.charAt(i) + returnString;
+            }
+            
+        }
+        
+        System.out.println("Return string: " + returnString);
+
+        String[] binaryStrings = new String[(int) Math.pow(2, xlist.size())];
+        
+        for (int i = 0; i < Math.pow(2, xlist.size()); i++) {
+            
+            String currentI = Integer.toBinaryString(i);
+            while (currentI.length() < xlist.size()) currentI = "0" + currentI;
+
+            String newAddress = returnString;
+            for (int j = 0; j < currentI.length(); j++) {
+                newAddress = newAddress.replaceFirst(Pattern.quote("X"), Matcher.quoteReplacement(Character.toString(currentI.charAt(j))));
+            }
+            
+            System.out.println("New address: " + newAddress);
+            binaryStrings[i] = newAddress;
+            
+        }
+        
+        long[] newAddresses = new long[binaryStrings.length];
+        for (int i = 0; i < newAddresses.length; i++) {
+            newAddresses[i] = toDenary(binaryStrings[i]);
+        }
+        
+        return newAddresses;
+
+    }
+    
+    static long toDenary(String binary) {
+        long value = 0;
+        for (int i = 0; i < binary.length(); i++) {
+            if (binary.charAt(i) == '1') {
+                value += Math.pow(2, (35 - i));
+            }
+        }
+        return value;
+    }
+    
+}