Word Search
Examples
Example 1:
Input: board = [
["A","B","C","D"],
["S","A","A","T"],
["A","C","A","E"]
],
word = "CAT"
Output: true
Example 2:
Input: board = [
["A","B","C","D"],
["S","A","A","T"],
["A","C","A","E"]
],
word = "BAT"
Output: false