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#1138 - Alphabet Board Path
Problem Description
On an alphabet board, we start at position (0, 0), corresponding to character board[0][0].
Here, board = ["abcde", "fghij", "klmno", "pqrst", "uvwxy", "z"], as shown in the diagram below.
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 board[r][c] at our current position (r, c) to the answer.
(Here, the only positions that exist on the board are positions with letters on them.) Return a sequence of moves that makes our answer equal to target in the minimum number of moves. You may return any path that does so.
Solution
/**
* @param {string} target
* @return {string}
*/
var alphabetBoardPath = function(target) {
let path = '';
let row = 0;
let col = 0;
for (const char of target) {
const code = char.charCodeAt(0) - 97;
const targetRow = Math.floor(code / 5);
const targetCol = code % 5;
while (row > targetRow) path += 'U', row--;
while (col > targetCol) path += 'L', col--;
while (row < targetRow) path += 'D', row++;
while (col < targetCol) path += 'R', col++;
path += '!';
}
return path;
};