Problem :2d grid , each node has 1+ colors; find number of clusters of a given color.
[[{red, blue, green}], [{blue, green}], [{green}]]
[[{blue}], [{yellow, green}], [{green}]]
[[{red, green}], [{red, green}], [{blue, green}]]
Output:
{ red -> 2, blue -> 2, green -> 1, yellow -> 1 }