Coding: Given a list of points, determine if they form a symmetric set (symmetric about some vertical line, such that for a point there is another point that is equidistant from the line). For example: (1,1), (2,5), (4,5), (5,1) - symmetric set about x = 3. If the input set had (2,2) it would not be symmetric.
Didn't found the leetcode example for this.