Add a solution for d3p1 and d3p2 in Java

day_03/java/generic.java

@@ -0,0 +1,87 @@
+package day_03.java;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.util.*;
+
+public class generic {
+	public static void main(String[] args) {
+		if (args.length < 2) {
+			System.out.println("Not enough args");
+			return;
+		};
+		Scanner s;
+		try {
+			s = generic.readFile(args[0]);
+		} catch (FileNotFoundException e) {
+			System.out.println("Can't find that file");
+			return;
+		}
+
+		Boolean part2 = args[1].equals("2");
+		Integer total = 0;
+		while (s.hasNextLine()) {
+			String c;
+			if (part2) {
+				c = generic.p2(s);
+			} else {
+				c = generic.p1(s);
+			}
+			Integer v = generic.priority(c);
+			total = total + v;
+		}
+		System.out.println(total);
+	}
+
+	public static String p1(Scanner file) {
+		String l = file.next();
+		Integer mid = l.length() / 2;
+		return generic.intersect(
+			l.substring(0, mid),
+			l.substring(mid)
+		);
+	}
+
+	public static String p2(Scanner file) {
+		String l1 = file.next();
+		String l2 = file.next();
+		String l3 = file.next();
+		return generic.intersect( l1, l2, l3 );
+	}
+
+	public static String intersect(String... s) {
+		Set<Character> intersection = generic.toSet(s[0]);
+		for (int i = 1; i < s.length; i++) {
+			intersection.retainAll(generic.toSet(s[i]));
+		}
+		if (intersection.size() == 1) {
+			return intersection.toArray()[0].toString();
+		}
+		return "";
+	}
+
+	public static Set<Character> toSet(String s) {
+		Set<Character> result = new HashSet<Character>();
+		for (int i = 0; i < s.length(); i++) {
+			result.add(s.charAt(i));
+		}
+		return result;
+	}
+
+	public static Integer priority(String s) {
+		char c = s.charAt(0);
+		Integer v = (int) c;
+		if (Character.isLowerCase(c)) {
+			return v - 96;
+		} else if (Character.isUpperCase(c)) {
+			return v - 38;
+		} else {
+			return 0;
+		}
+	}
+
+	public static Scanner readFile(String path) throws FileNotFoundException {
+		File f = new File(path);
+		return new Scanner(f);
+	}
+}