Thanks in advance for attention to this 5-year old problem.
Example input:
5 4
1 2 2
4 1 4
4 2 4
3 1 4
Example output: (generated by Accepted submissions / editorial algorithm, but I do not understand. Can be verified by 67085154)
3
4 1 6
4 2 2
3 2 4
I don't see a way to increase the edge 4-1 to a weight 6, by the operations described in the problem statement.
First do an operation with a=4, b=2, c=3, d=1, z=4; that removes the 3->1 and 4->2 debts, adds 3->2 with debt 4 and makes the debt of 4->1 8. From there, an operation with a=4, b=1, c=1, d=2, z=2 gets you to the final graph.
Thanks so much for your reply. sorry for my stupidity.
Job isn't the only thing you seeking imo. :)