Do not use signed char (C++) or signed byte (C#) to store convivality, or you get wrong results because of overflow.

The test 5 is:
7
1
1
100
100
1
1
1
1 3
2 3
6 4
7 4
4 5
3 5
0 0

After you sum 100 + 100, you get -56 in the signed char/signed byte variable, while the right sum should be 200.

Hope this helps.