Trying to create a tree in matrix form

Hey all,

I got an input matrix P, where each number represents a task:

P = [1 2;1 5;2 4;5 3;2 6;4 7]

[1 2;1 5] should be read as, task 2 start after task 1, and task 5 starts after task 1

Now lets say we start with task 1, i want to compute the tree structure, which should be:

In matrix form i would like it to be:

Output = [1 2 6 0;1 2 4 7;1 5 3 0]

I am having trouble converting P to the desired Output matrix, any idea's are welcome.

Thanks in advance

Answer 1

[Steven Lord]

This doesn't exactly get you the format you want, but it gets you something pretty close.

P = [1 2;1 5;2 4;5 3;2 6;4 7];
D = digraph(P(:, 1), P(:, 2));
leaves = outdegree(D) == 0;
tree = shortestpathtree(D, 1, find(leaves), 'OutputForm', 'cell')

Each cell in the tree cell array contains the shortest path from 1 to the corresponding leaf node.

[Niels de Vries]

This is even better tbh, thanks !