floodfill算法系列一＞图像渲染

class Solution { 
    int m,n,sr,sc;
    int prev;

    public int[][] floodFill(int[][] image, int sr, int sc, int color) {

        if(image[sr][sc] == color) return image;

        m = image.length;
        n = image[0].length;
        prev = image[sr][sc];

        dfs(image,sr,sc, color);
 
            
        return image;
    } 

    int[] dx = {0,0,-1,1}; 
    int[] dy = {-1,1,0,0};
    private void dfs(int[][] image, int i, int j, int color){
        image[i][j] = color;

        for(int k = 0; k < 4; k++){
            int x = i + dx[k]; int y = j + dy[k];
            if(x >= 0 && x < m && y >= 0 && y < n && prev == image[x][y]){
                dfs(image,x,y,color);
            }
        }

    }
}