1034. Coloring A Border.java

class Solution {
    public int[][] colorBorder(int[][] grid, int row, int col, int color) {
        dfs(grid, row, col, grid[row][col]);
        
        for(int i = 0; i < grid.length; i++)
        {
            for(int j = 0; j < grid[0].length; j++)
            {
                if(grid[i][j] < 0)
                    grid[i][j] = color;
            }
        }
        
        return grid;
    }
    
    int[][] dirs = new int[][]{ {1,0}, {-1, 0}, {0,1}, {0,-1} };
    public void dfs(int[][] grid, int r, int c, int clr)
    {
        if(r < 0 || c < 0 || r >= grid.length || c >= grid[0].length || Math.abs(grid[r][c]) != clr)
            return;

        grid[r][c] = -clr;
        int count = 0;
        
        for(int i = 0; i < 4; i++)
        {
            int rowdash = dirs[i][0] + r;
            int coldash = dirs[i][1] + c;
            
            if(rowdash < 0 || coldash < 0 || rowdash >= grid.length || coldash >= grid[0].length || Math.abs(grid[rowdash][coldash]) != clr)
                continue;
            
            count++;
            
            if(grid[rowdash][coldash] == clr)
            {
                dfs(grid, rowdash, coldash, clr);
            }
            
        }
        

        if(count == 4)
        {
            grid[r][c] = clr;
        }
        
    }
}