Complete day 2

src/main/java/com/mattrixwv/adventOfCode24/ProblemSelector.java

@@ -9,12 +9,14 @@ import java.util.StringJoiner;
 import com.mattrixwv.adventOfCode24.days.Problem;
 import com.mattrixwv.adventOfCode24.days.Problem1;
 import com.mattrixwv.adventOfCode24.days.Problem2;
+import com.mattrixwv.adventOfCode24.days.Problem3;
+import com.mattrixwv.adventOfCode24.days.Problem4;
 
 
 public class ProblemSelector{
 	private static final Scanner input = new Scanner(System.in);
 	//Holds the valid problem numbers
-	protected static final List<Integer> PROBLEM_NUMBERS = List.of(0, 1, 2);
+	protected static final List<Integer> PROBLEM_NUMBERS = List.of(0, 1, 2, 3, 4);
 
 
 	private ProblemSelector(){
@@ -28,6 +30,8 @@ public class ProblemSelector{
 		switch(dayNumber){
 			case 1  : day = new Problem1(); break;
 			case 2  : day = new Problem2(); break;
+			case 3  : day = new Problem3(); break;
+			case 4  : day = new Problem4(); break;
 			default: throw new InvalidParameterException();
 		}
 		return day;

src/main/java/com/mattrixwv/adventOfCode24/days/Problem2.java

@@ -1,5 +1,6 @@
 package com.mattrixwv.adventOfCode24.days;
 
+
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -7,6 +8,7 @@ import java.util.Scanner;
 
 import com.mattrixwv.Stopwatch;
 
+
 public class Problem2 extends Problem{
 	private static final String inputFileName = "days/Problem1.txt";
 

src/main/java/com/mattrixwv/adventOfCode24/days/Problem3.java

@@ -0,0 +1,142 @@
+package com.mattrixwv.adventOfCode24.days;
+
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+
+import com.mattrixwv.Stopwatch;
+
+
+public class Problem3 extends Problem{
+	private static final String inputFileName = "days/Problem3.txt";
+
+
+	public Problem3(){
+		super();
+		description = "Find the \"safe\" reports from the given list.";
+		result = "Unresolved";
+	}
+
+
+	public String runSolution(){
+		Stopwatch timer = new Stopwatch();
+		timer.start();
+
+		List<String> reports = new ArrayList<>();
+		int safeReports = 0;
+
+
+		//Read elements from the file
+		try(Scanner scanner = new Scanner(this.getClass().getClassLoader().getResourceAsStream(inputFileName))){
+			scanner.useDelimiter("\n");
+			while(scanner.hasNext()){
+				String report = scanner.next();
+				if(!report.isBlank()){
+					reports.add(report);
+				}
+			}
+		}
+
+		//Count how many reports are safe
+		for(String report : reports){
+			if(isSafeReport(convertReportToArray(report), false)){
+				++safeReports;
+			}
+		}
+
+		//Save the results
+		timer.stop();
+		result = "The number of safe reports is " + safeReports + ".\nIt took " + timer.toString() + " to run the algorithm.";
+
+		return result;
+	}
+
+	private boolean isSafeReport(int[] elements, boolean recursive){
+		boolean isSafe = false;
+		//Check if the array is long enough
+		if(elements.length <= 1){
+			isSafe = true;
+		}
+		//Check if the first tow elements are ascending or descending
+		else if(elements[0] > elements[1]){
+			isSafe = isSafeDescending(elements);
+		}
+		else if(elements[0] < elements[1]){
+			isSafe = isSafeAscending(elements);
+		}
+		//If the elements are the same that violates a rule, so it is unsafe
+		else{
+			isSafe = false;
+		}
+
+		return isSafe;
+	}
+
+	private boolean isSafeAscending(int[] elements){
+		if(elements.length <= 1){
+			return true;
+		}
+
+		int lastElement = elements[0];
+		for(int cnt = 1;cnt < elements.length;++cnt){
+			int currentElement = elements[cnt];
+			//If one of the elements is less than or equal to the last, then it is not ascending
+			if(currentElement <= lastElement){
+				return false;
+			}
+			//If one of the elements is more than 3 larger than the last, then it is unsafe
+			else if((currentElement - 3) > lastElement){
+				return false;
+			}
+			//If neither of the above triggers is hit then these two elements are safe, proceed to the next
+			else{
+				lastElement = currentElement;
+			}
+		}
+		//If the function was never triggered to return false, then return true
+		return true;
+	}
+
+	private boolean isSafeDescending(int[] elements){
+		if(elements.length <= 1){
+			return true;
+		}
+
+		int lastElement = elements[0];
+		for(int cnt = 1;cnt < elements.length;++cnt){
+			int currentElement = elements[cnt];
+			//If one of the elements is greater than or equal to the last, then it is not descending
+			if(currentElement >= lastElement){
+				return false;
+			}
+			//If one of the elements is more than 3 smaller than the last, then it is unsafe
+			else if((currentElement + 3) < lastElement){
+				return false;
+			}
+			//If neither of the above trigger is hit then these two elements are safe, proceed to the next
+			else{
+				lastElement = currentElement;
+			}
+		}
+		//If the function was never triggered to return false, then return true
+		return true;
+	}
+
+	private int[] convertReportToArray(String report){
+		//Split the report on space to get the individual elements
+		String[] elementsString = report.split(" ");
+		//Convert the elements to integers
+		int[] elements = new int[elementsString.length];
+		for(int cnt = 0;cnt < elementsString.length;++cnt){
+			elements[cnt] = Integer.parseInt(elementsString[cnt]);
+		}
+		return elements;
+	}
+}
+
+/*
+Find the "safe" reports from the given list.
+The number of safe reports is 502.
+It took 15.010 milliseconds to run the algorithm.
+*/

src/main/java/com/mattrixwv/adventOfCode24/days/Problem4.java

@@ -0,0 +1,161 @@
+package com.mattrixwv.adventOfCode24.days;
+
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+
+import com.mattrixwv.Stopwatch;
+
+
+public class Problem4 extends Problem{
+	private static final String inputFileName = "days/Problem3.txt";
+
+
+	public Problem4(){
+		super();
+		description = "Find the \"safe\" reports from the given list.";
+		result = "Unresolved";
+	}
+
+
+	public String runSolution(){
+		Stopwatch timer = new Stopwatch();
+		timer.start();
+
+		List<String> reports = new ArrayList<>();
+		int safeReports = 0;
+
+
+		//Read elements from the file
+		try(Scanner scanner = new Scanner(this.getClass().getClassLoader().getResourceAsStream(inputFileName))){
+			scanner.useDelimiter("\n");
+			while(scanner.hasNext()){
+				String report = scanner.next();
+				if(!report.isBlank()){
+					reports.add(report);
+				}
+			}
+		}
+
+		//Count how many reports are safe
+		for(String report : reports){
+			if(isSafeReport(convertReportToArray(report), false)){
+				++safeReports;
+			}
+		}
+
+		//Save the results
+		timer.stop();
+		result = "The number of safe reports is " + safeReports + ".\nIt took " + timer.toString() + " to run the algorithm.";
+
+		return result;
+	}
+
+	private boolean isSafeReport(int[] elements, boolean recursive){
+		boolean isSafe = false;
+		//Check if the array is long enough
+		if(elements.length <= 1){
+			isSafe = true;
+		}
+		//Check if the first tow elements are ascending or descending
+		else if(elements[0] > elements[1]){
+			isSafe = isSafeDescending(elements);
+			for(int cnt = 0;(!recursive) && (!isSafe) && (cnt < elements.length);++cnt){
+				isSafe = isSafeReport(removeElement(elements, cnt), true);
+			}
+		}
+		else if(elements[0] < elements[1]){
+			isSafe = isSafeAscending(elements);
+			for(int cnt = 0;(!recursive) && (!isSafe) && (cnt < elements.length);++cnt){
+				isSafe = isSafeReport(removeElement(elements, cnt), true);
+			}
+		}
+		//If the elements are the same that violates a rule, so it is unsafe
+		else{
+			for(int cnt = 0;(!recursive) && (!isSafe) && (cnt < elements.length);++cnt){
+				isSafe = isSafeReport(removeElement(elements, cnt), true);
+			}
+		}
+
+		return isSafe;
+	}
+
+	private boolean isSafeAscending(int[] elements){
+		if(elements.length <= 1){
+			return true;
+		}
+
+		int lastElement = elements[0];
+		for(int cnt = 1;cnt < elements.length;++cnt){
+			int currentElement = elements[cnt];
+			//If one of the elements is less than or equal to the last, then it is not ascending
+			if(currentElement <= lastElement){
+				return false;
+			}
+			//If one of the elements is more than 3 larger than the last, then it is unsafe
+			else if((currentElement - 3) > lastElement){
+				return false;
+			}
+			//If neither of the above triggers is hit then these two elements are safe, proceed to the next
+			else{
+				lastElement = currentElement;
+			}
+		}
+		//If the function was never triggered to return false, then return true
+		return true;
+	}
+
+	private boolean isSafeDescending(int[] elements){
+		if(elements.length <= 1){
+			return true;
+		}
+
+		int lastElement = elements[0];
+		for(int cnt = 1;cnt < elements.length;++cnt){
+			int currentElement = elements[cnt];
+			//If one of the elements is greater than or equal to the last, then it is not descending
+			if(currentElement >= lastElement){
+				return false;
+			}
+			//If one of the elements is more than 3 smaller than the last, then it is unsafe
+			else if((currentElement + 3) < lastElement){
+				return false;
+			}
+			//If neither of the above trigger is hit then these two elements are safe, proceed to the next
+			else{
+				lastElement = currentElement;
+			}
+		}
+		//If the function was never triggered to return false, then return true
+		return true;
+	}
+
+	private int[] removeElement(int[] elements, int location){
+		int[] newElements = new int[elements.length - 1];
+		int newCnt = 0;
+		for(int cnt = 0;cnt < elements.length;++cnt){
+			if(cnt != location){
+				newElements[newCnt++] = elements[cnt];
+			}
+		}
+		return newElements;
+	}
+
+	private int[] convertReportToArray(String report){
+		//Split the report on space to get the individual elements
+		String[] elementsString = report.split(" ");
+		//Convert the elements to integers
+		int[] elements = new int[elementsString.length];
+		for(int cnt = 0;cnt < elementsString.length;++cnt){
+			elements[cnt] = Integer.parseInt(elementsString[cnt]);
+		}
+		return elements;
+	}
+}
+
+/*
+Find the "safe" reports from the given list.
+The number of safe reports is 544.
+It took 5.181 milliseconds to run the algorithm.
+*/