Finding Ocean - Airbnb

https://github.com/allaboutjst/airbnb/blob/master/README.md

Given: An array of strings where L indicates land and W indicates water, and a coordinate marking a starting point in the middle of the ocean.

Challenge: Find and mark the ocean in the map by changing appropriate Ws to Os.

• An ocean coordinate is defined to be the initial coordinate if a W, and
• any coordinate directly adjacent to any other ocean coordinate.

void findOcean(String[] map, int row, int column);
String[] map = new String[]{
 "WWWLLLW",
 "WWLLLWW",
 "WLLLLWW"
};
printMap(map);

STDOUT:
WWWLLLW
WWLLLWW
WLLLLWW

findOcean(map, 0, 1);
printMap(map);

STDOUT:
OOOLLLW
OOLLLWW
OLLLLWW




https://github.com/allaboutjst/airbnb/blob/master/src/main/java/finding_ocean/FindingOcean.java

        public void floodFill(char[][] board, int i, int j, char oldColor, char newColor) {
            if (board[i][j] != oldColor || board[i][j] == newColor) {
                return;
            }

            Queue<Integer> queue = new LinkedList<>();
            queue.add(i * board[0].length + j);
            board[i][j] = newColor;

            while (!queue.isEmpty()) {
                int pos = queue.poll();
                int m = pos / board[0].length;
                int n = pos % board[0].length;

                if (m + 1 < board.length && board[m + 1][n] == oldColor) {
                    queue.add((m + 1) * board[0].length + n);
                    board[m + 1][n] = newColor;
                }
                if (m - 1 >= 0 && board[m - 1][n] == oldColor) {
                    queue.add((m - 1) * board[0].length + n);
                    board[m - 1][n] = newColor;
                }
                if (n + 1 < board[0].length && board[m][n + 1] == oldColor) {
                    queue.add(m * board[0].length + n + 1);
                    board[m][n + 1] = newColor;
                }
                if (n - 1 >= 0 && board[m][n - 1] == oldColor) {
                    queue.add(m * board[0].length + n - 1);
                    board[m][n - 1] = newColor;
                }
            }
        }