solve = function solve(board) {
    searchRows(board);/* Time O(ROWS * COLS) | Space O(ROWS * COLS) */
    searchCols(board);/* Time O(ROWS * COLS) | Space O(ROWS * COLS) */
    searchGrid(board);/* Time O(ROWS * COLS) | Space O(ROWS * COLS) */
}
https://leetcode.com/problems/surrounded-regions/
Time O(ROWS * COLS) | Space O(ROWS * COLS)
@param {character[][]} board
@return {void} Do not return anything, modify board in-place instead.