bombEnemy.java

//  Given a 2D grid, each cell is either a wall 'W', an enemy 'E' or empty '0' (the number zero), return the maximum enemies you can kill using one bomb.
// The bomb kills all the enemies in the same row and column from the planted point until it hits the wall since the wall is too strong to be destroyed.
// Note that you can only put the bomb at an empty cell.

// Example:
// For the given grid

// 0 E 0 0
// E 0 W E
// 0 E 0 0

// return 3. (Placing a bomb at (1,1) kills 3 enemies)

 public class Solution {

     public int maxKilledEnemies(char[][] grid) {

        if(grid == null || grid.length == 0 ||  grid[0].length == 0) return 0;

        int max = 0;
        int row = 0;
        int[] col = new int[grid[0].length];

        for(int i = 0; i<grid.length; i++) {

            for(int j = 0; j<grid[0].length;j++) {

                if(grid[i][j] == 'W') continue;
                if(j == 0 || grid[i][j-1] == 'W') {

                     row = killedEnemiesRow(grid, i, j);

                }

                if(i == 0 || grid[i-1][j] == 'W') {

                     col[j] = killedEnemiesCol(grid,i,j);

                }

                if(grid[i][j] == '0') {

                    max = (row + col[j] > max) ? row + col[j] : max;

                }

            }

        }
        
        return max;

    }

    //calculate killed enemies for row i from column j
    private int killedEnemiesRow(char[][] grid, int i, int j) {

        int num = 0;

        while(j <= grid[0].length-1 && grid[i][j] != 'W') {

            if(grid[i][j] == 'E') num++;
            j++;

        }

        return num;

    }

    //calculate killed enemies for  column j from row i
    private int killedEnemiesCol(char[][] grid, int i, int j) {

        int num = 0;

        while(i <= grid.length -1 && grid[i][j] != 'W'){

            if(grid[i][j] == 'E') num++;
            i++;

        }

        return num;

    }

}