Solution2.go

func floodFill(image [][]int, sr int, sc int, color int) [][]int {
	if image[sr][sc] == color {
		return image
	}
	oc := image[sr][sc]
	q := [][]int{[]int{sr, sc}}
	image[sr][sc] = color
	dirs := []int{-1, 0, 1, 0, -1}
	for len(q) > 0 {
		p := q[0]
		q = q[1:]
		for k := 0; k < 4; k++ {
			x, y := p[0]+dirs[k], p[1]+dirs[k+1]
			if x >= 0 && x < len(image) && y >= 0 && y < len(image[0]) && image[x][y] == oc {
				q = append(q, []int{x, y})
				image[x][y] = color
			}
		}
	}
	return image
}