733. Flood Fill.cpp

// https://leetcode.com/problems/flood-fill/

class Solution
{
public:
    vector<vector<int>> floodFill(vector<vector<int>> &image, int sr, int sc, int newColor)
    {
        if (image[sr][sc] == newColor)
            return image;
        DFS(image, sr, sc, image[sr][sc], newColor);
        return image;
    }

    void DFS(vector<vector<int>> &image, int sr, int sc, int oldColor, int newColor)
    {
        if (sr < 0 || sr >= image.size() || sc < 0 || sc >= image[sr].size() || image[sr][sc] != oldColor)
            return;

        image[sr][sc] = newColor;
        DFS(image, sr + 1, sc, oldColor, newColor);
        DFS(image, sr - 1, sc, oldColor, newColor);
        DFS(image, sr, sc + 1, oldColor, newColor);
        DFS(image, sr, sc - 1, oldColor, newColor);
    }
};