Java_Programs/BattleshipsInABoard.java at main · jvm-coder/Java_Programs · GitHub

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// https://leetcode.com/problems/battleships-in-a-board/

//Solution 1
class Solution {
    public int countBattleships(char[][] board) {
        int numBattleships = 0;
        for(int i=0; i<board.length; i++) {
            for(int j=0; j<board[i].length; j++) {
                if(board[i][j] == '.') {
                    continue;
                }

                if(i>0 && board[i-1][j] == 'X') {
                    continue;
                }

                if(j>0 && board[i][j-1] == 'X') {
                    continue;
                }

                numBattleships++;
            }
        }

        return numBattleships;
    }

}


// Solution 2

class Solution {
    public int countBattleships(char[][] board) {
        int numBattleships = 0;
        for(int i=0; i<board.length; i++) {
            for(int j=0; j<board[i].length; j++) {
                if(board[i][j] == 'X') {
                    numBattleships++;
                    sink(board, i, j);
                }
            }
        }

        return numBattleships;
    }

    public void sink(char[][] board, int i, int j) {
        if(i<0 || i>= board.length || j<0 || j>= board[i].length || board[i][j] != 'X') {
            return;
        }

        board[i][j] = '.';
        sink(board, i+1, j);
        sink(board, i-1, j);
        sink(board, i, j+1);
        sink(board, i, j-1);
    }
}