IrreducibleNumber

nice SRM i solved the 3 problems :D :D
public class IrreducibleNumber {
	public static int getIrreducible(int[] A) {
		int a = 1;
		while (true) {
			if (cansum(A, a))
				break;
			else
				a++;

		}
		return a;

	}

	private static boolean cansum(int[] A, int a2) {
		int sum = 0;
		for (int i = 0; i < A.length; i++) {
			if (A[i] == a2)
				return false;
			sum += A[i];
		}
		if (a2 == sum)
			return false;
		int s1 = A[0];
		int s2 = (A.length > 1) ? A[1] : 0;
		int s3 = (A.length > 2) ? A[2] : 0;
		if (s1 + s2 == a2)
			return false;
		else if (s2 + s3 == a2)
			return false;
		else if (s1 + s3 == a2)
			return false;
		return true;

	}
}
			

			
						

RoadsAndFools

public class RoadsAndFools {
	static int score;
	static String string;

	public static String determineOrientation(int length, int[] frontSides) {
		score = 0;
		int prev = -1;
		String s = "";
		dfs(frontSides[0], prev, frontSides, length, frontSides[0] + "", 1);
		if (length - frontSides[0] != frontSides[0])
		dfs(length - frontSides[0], prev, frontSides, length,
				(length - frontSides[0]) + "", 1);
		if (score > 1)
			return "MULTIPLE SOLUTIONS";
		else if (score == 0)
			return "NO SOLUTION";
		else
			return string;

	}

	private static void dfs(int i, int prev, int[] frontSides, int length,
			String s, int counter) {
		if (prev >= i)
			return;
		else if (counter == frontSides.length) {
			string = s;
			score++;
		} else {
			prev = i;
			dfs(frontSides[counter], prev, frontSides, length, s + " "
					+ frontSides[counter], counter + 1);
			if (length - frontSides[counter] != frontSides[counter])
				dfs(length - frontSides[counter], prev, frontSides, length, s
						+ " " + (length - frontSides[counter]), counter + 1);
		}

	}

	public static void main(String[] args) {
		int[] a = { 5 };
		System.out.println(determineOrientation(10, a));
	}
}

UnrepeatableWords

public class UnrepeatableWords {
	static String alp = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
	static String ans = "";
	static boolean check = true;

	public static String getWord(int k, int n, int allowed) {
		dfs("A", k, n, allowed, 1);
		return ans;
	}

	private static void dfs(String string, int k, int n, int allowed, int i) {
		if (i == n&&check(string,k)) {
			ans = string;
			check = false;
		} else if (!check(string, k))
			return;
		else {
			for (int j = 0; j < allowed && check; j++) {
				dfs(string + alp.charAt(j), k, n, allowed, i + 1);
			}
		}

	}

	private static boolean check(String string, int k) {
		String out = "";
		for (int i = 0; i < string.length(); i++)
			out = string.charAt(i) + out;
		int n = string.length();
		for (int l = 1; l <= n / k; l++) {
			int count = 0;
			for (int i = 0; i < k - 1; i++) {
				if (out.substring(i * l, i * l + l).equals(
						out.substring((i + 1) * l, (i + 1) * l + l))) {
					count++;
				}
			}
			if (count == k - 1)
				return false;
		}

		return true;
	}
}