You are given a map consisting of a number of regions. Your task is to color each region with one of four colors, in such a way that no two regions sharing a boundary have the same color. You are provided with some regions already colored, sufficient to make the remainder of the solution unique.
Only regions which share a length of border are required to be different colors. Two regions which meet at only one point (i.e. are diagonally separated) may be the same color.