2026/05/16

[LeetCode] 733 Flood Fill

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
class Solution {
private:
  int N, M;
  int dirX[4] = {0, 1, 0, -1};
  int dirY[4] = {1, 0, -1, 0};
  void dfs(int x, int y, int color, vector<vector<int>> &image) {
    int originalColor = image[x][y];
    if (originalColor == color)
      return;
    image[x][y] = color;
    for (int i = 0; i < 4; i++) {
      int dx = x + dirX[i];
      int dy = y + dirY[i];
      if (dx >= 0 && dx < N && dy >= 0 && dy < M &&
          image[dx][dy] == originalColor)
        dfs(dx, dy, color, image);
    }
  }

public:
  vector<vector<int>> floodFill(vector<vector<int>> &image, int x, int y,
                                int color) {
    N = image.size();
    M = image[0].size();
    dfs(x, y, color, image);
    return image;
  }
};