AdjacentLetters.java

package com.stackexchange.puzzling;

import java.awt.Point;
import java.io.BufferedReader;
import java.io.FileReader;
import java.util.HashMap;
import java.util.Map;

public class AdjacentLetters {
	public static void main(String[] args) throws Exception {
		String[] rows = new String[] { "qwertyuiop", "asdfghjkl", "zxcvbnm" };
		for (int i = 0; i < rows.length; i++) {
			for (int j = 0; j < rows[i].length(); j++) {
				locations.put(rows[i].charAt(j), new Point(j * 2 + i, i));
			}
		}

		System.out.println(isAdjacentIsogram("zsedcvg"));

		BufferedReader reader = new BufferedReader(new FileReader("wordlist.txt"));
		String line, longestMatch = "";
		while ((line = reader.readLine()) != null) {
			if (line.length() < longestMatch.length())
				continue;
			if (!isAdjacentIsogram(line))
				continue;
			longestMatch = line;
			System.out.println(line);
		}
	}

	private static Map<Character, Point> locations = new HashMap<>();

	private static boolean isAdjacentIsogram(String word) {
		boolean[] used = new boolean[26];
		Point currentPoint = null;
		for (int i = 0; i < word.length(); i++) {
			char c = Character.toLowerCase(word.charAt(i));
			if (used[c - 'a'])
				return false;
			used[c - 'a'] = true;
			Point point = locations.get(c);
			if (currentPoint != null
					&& (Math.abs(currentPoint.x - point.x) > 2 || Math.abs(currentPoint.y - point.y) > 1))
				return false;
			currentPoint = point;
		}
		return true;
	}
}