Hello!

I was toying with visualgo.net to create some test cases, and I found this example which per visualgo should have maxflow of 28 from node 0 to 7, and your library calculates it as 29:

8 15
0 1 10 
0 2 5 
0 3 15 
1 2 4 
1 4 9 
1 5 15 
2 3 4 
2 5 8 
3 6 16 
4 5 15 
4 7 10 
5 6 15 
5 7 10 
6 2 6 
6 7 10

This text can be pasted in Edit graph -> Input graph, in the lower left corner. Note that you should choose 0-based indexing there.
Also, be aware that graph editing is quite buggy there, what I mean is that visualgo will often complain that the 0 node is not the leftmost one, and 7 node is not a rightmost one. Although it is drawn the graph itself. Just repeat pressing Input graph -> paste -> Submit few times, until it will draw them the way it wants.

And then from the same corner you can start one of the three algorithms. All three give 28.