Bomb Enemy

public class Solution {
    public int maxKilledEnemies(char[][] grid) {
        if (grid.length == 0 || grid[0].length == 0) {
            return 0;
        }
        int result = 0;
        int rowCount = 0;
        int[] colCount = new int[grid[0].length];

        for (int i = 0; i < grid.length; i++) {
            for (int j = 0; j < grid[0].length; j++) {
                if (j == 0 || grid[i][j-1] == 'W') {
                    rowCount = 0;
                    for (int k = j; k < grid[0].length && grid[i][k] != 'W'; k++) {
                        rowCount += grid[i][k] == 'E' ? 1 : 0;
                    }
                }
                
                if (i == 0 || grid[i-1][j] == 'W') {
                    colCount[j] = 0;
                    for (int k = i; k < grid.length && grid[k][j] != 'W'; k++) {
                        colCount[j] += grid[k][j] == 'E' ? 1 : 0;
                    }
                }
                if (grid[i][j] == '0') {
                    result = Math.max(result, rowCount + colCount[j]);;;
                }
            }
        }
        return result;
    }
}

 

Since the traversal is row by row. So the only one row count is enough.

Three conditions are:

1. j == 0 (new line start) or previous column is wall. Recalcuate the row count until end or meet wall.

2. i == 0 (starting row) or previous row is wall. Recalculate the column count untl end or meet wall

3. current val is "0", compare the result.