[2017-04-26] Challenge #312 [Intermediate] Next largest number

dailyprogrammer.java

package dailyprogrammer;

import java.util.Arrays;


/**
 * https://www.reddit.com/r/dailyprogrammer/comments/67q3s6/20170426_challenge_312_intermediate_next_largest/
 * @author David
 *
 */
public class NextInt {
	public static void main(String[] args) {
		System.out.println(next(1234));
		System.out.println(next(1243));
		System.out.println(next(234765));
		System.out.println(next(19000));
	}
	
	
	public static int next(int a) {
		for (int i = a + 1; i < Integer.MAX_VALUE; i++) {
			if (sameDigits(a, i)) return i;
		}
		throw new Error();
	}
	
	public static boolean sameDigits(int a, int b) {
		char[] ac = Integer.toString(a).toCharArray();
		Arrays.sort(ac);
		char[] bc = Integer.toString(b).toCharArray();
		Arrays.sort(bc);
		return equals(ac, bc);
	}
	
	public static boolean equals(char[] a, char[] b) {
		if (a.length != b.length) return false;
		
		for (int i = 0; i < a.length; i++) {
			if (a[i] != b[i]) return false;
		}
		return true;
	}
}