Alphabet Board Path

On an alphabet board, we start at position (0, 0), corresponding to character board[0][0].

The board is defined as:

board = ["abcde", "fghij", "klmno", "pqrst", "uvwxy", "z"]

We may make the following moves:

• 'U' moves our position up one row, if the position exists on the board
• 'D' moves our position down one row, if the position exists on the board
• 'L' moves our position left one column, if the position exists on the board
• 'R' moves our position right one column, if the position exists on the board
• '!' adds the character at our current position to the answer

Return a sequence of moves that makes our answer equal to target in the minimum number of moves. You may return any valid path.