Memory                        Active
-------------------------      -------
Address Contents Pointer

0       134431   X---------->  0
1       938434      -------->  4
2       432754      |  ----->  6
3       292343      |  |
4       874944   X---  |
5       002345         |
6       654243   X------
7       112903

Figure 4: How to avoid initializing memory using double bookkeeping.