Use a customer-by-customer table for all 15 pairs

Use indices only as local labels: 1 Abhinav, 2 Akshaya, 3 Ahmed, 4 Srivatsan, 5 Advaith, 6 Vignesh. These are not bill numbers or permanent customer IDs. Hold one row fixed and advance the column; then move to the next row. Rows and columns now represent the SAME customer set, unlike the customer-by-category profile table.

Only the upper triangle is stored here. A dash means “not stored in this triangular representation”, not zero distance and not missing source data. The omitted diagonal would be zero; the lower triangle would mirror the upper triangle. The lecturing discussion contains some spoken table slips; these entries are recomputed from the original five-category profiles.

foreach i in [1,2,3,4,5,6] {
    foreach j in [1,2,3,4,5,6] {
        if (i < j) {
            record(i,j,distance(profile[i],profile[j]))
        }
    }
}