crawa:similar to Spirals made of line segments, with a small change

reverse:Construct an weighted undirected graph with 0 and 1 as weights: Assign weights in the following manner, if a and b are vertices then... if only a--->b exists then assign '0' and if not a <--- b then '1' if both a-->b and a<--b exists the both weights are '0'

Ex: 7 7 1 2 3 2 3 4 7 4 6 2 5 6 7 5 undirected graph with adjacency list representation including weights: {0: {1: 0}, 1: {0: 1, 2: 1, 5: 1}, 2: {1: 0, 3: 0}, 3: {2: 1, 6: 1}, 4: {5: 0, 6: 1}, 5: {1: 0, 4: 1}, 6: {3: 0, 4: 0}} 2

use Dijkstra's algorithm with heap to select mini weight vertex