The Floyd-Waarshall algorithm (also known as the WFI algorithm) is an algorithm for finding the shortest paths between all of the points of a graph. Also, this graph can be a weighted graph with positive or negative vertices (but with no negative cycles).
First of all you need a graph like Below:
Then we should make a matrix of paths (i is the start point and j is the finish point); if i equals j, we put 0, if the start point and end point don't have neighbors, we put infinite, and if two points are neighbors, we put the degree of the start point. Look at the below matrix
And then we have to change the values to the shortest paths.