keys:  0  .  7  3  4 10 13 30 15 18 19 34 21 22 24  . 26  .  . 29
index: 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19

Figure 3: Collapsing shifted rows down into hash table C.