Matrix Letter Challenge

ArrayMatrix

Given a matrix of characters where each cell contains a lowercase letter, determine the longest contiguous line (either horizontal, vertical, or diagonal) of repeated characters and return that letter along with the length as a formatted string. Example output: a-4 means the letter 'a' is the longest with a repeated line of length 4 in any direction.

Example 1

Input

[
  [
    "a",
    "b",
    "c"
  ],
  [
    "d",
    "c",
    "b"
  ],
  [
    "g",
    "b",
    "b"
  ]
]

Output

b-3

Explanation. The letter 'b' forms the longest contiguous line of 3 vertically on the right side of the matrix.

Example 2

Input

[
  [
    "z",
    "z",
    "z"
  ],
  [
    "b",
    "z",
    "a"
  ],
  [
    "c",
    "d",
    "e"
  ]
]

Output

z-3

Explanation. The letter 'z' forms the longest contiguous horizontal line at the top of the matrix.

Example 3

Input

[
  [
    "x",
    "y",
    "z"
  ],
  [
    "a",
    "x",
    "c"
  ],
  [
    "b",
    "w",
    "x"
  ]
]

Output

x-3

Explanation. The letter 'x' forms the longest diagonal from the top left to the bottom right.

Follow-up: Can you optimize your solution to minimize the number of passes you need to do through the matrix?

Constraints:

The input matrix will be a non-empty 2D array of lowercase letters. Minimum matrix size will be 1x1.

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