Given a string path, where path[i] = 'N', 'S', 'E' or 'W', each representing moving one unit north, south, east, or west, respectively. You start at the origin (0, 0) on a 2D plane and walk on the path specified by path. Return true if the path crosses itself at any point, that is, if at any time you are on a location you have previously visited. Return false otherwise.