How to read a QCVRP instance file:

First line:	N	depot

Second line:	K	Q

Third line:	2N entries containing the demands and costs for single-customer routes. To read them we do:

for(i = 0; i < N; ++ i)
	in >> d[i] >> c[0][i];

Following lines: Quadratic costs. To read them we proceed as follows:
for(i = 0; i < N; ++ i)
	for(j = 0; j < N; ++ j)
		for(k = i + 1; k < N; ++ k)
			if(i != j && j != k && j != depot)
				in >> c[i][j][k];

-----------------------------------------------
Legend:
N		:	Total number of nodes (number of customers + 1)
depot		:	Index of the depot node (normally 0).
K		:	Number of vehicles
Q		:	Vehicle capacity
d[i]		:	Demand of node i
c[0][i]		:	Cost of single customer route 0-i-0.
c[i][j][k]	:	Cost of q-edge ({i,k}, j).