public String alphabetBoardPath(String target) {

Map<Character, Integer[]> map = new HashMap<>();

for (char i = 'a'; i <= 'z'; i++)

map.put(i, new Integer[] {(i - 97) / 5, (i - 97) % 5 });

char prev = 'a';

StringBuilder res = new StringBuilder();

for (int i = 0; i < target.length(); i++) {

char currChar = target.charAt(i);

int xDiff = map.get(currChar)[1] - map.get(prev)[1];

int yDiff = map.get(currChar)[0] - map.get(prev)[0];

if (yDiff != 0)

for (int j = 0; j < Math.abs(yDiff); j++)

if (yDiff > 0) res.append('D'); else res.append('U');

if (currChar == 'z' && prev != 'z')

res.setLength(res.length() - 1);

if (xDiff != 0)

for (int j = 0; j < Math.abs(xDiff); j++)

if (xDiff > 0) res.append('R'); else res.append('L');

if (currChar == 'z' && prev != 'z')

res.append('D');

res.append('!');

prev = currChar;

}

return res.toString();

}

public static void main(String[] args) {

AlphabetBoardPath sln = new AlphabetBoardPath();

System.out.println(sln.alphabetBoardPath("zz"));

System.out.println(sln.alphabetBoardPath("aa"));

System.out.println(sln.alphabetBoardPath("aba"));

}