Malloc decrease 'report' by using sort of geometric expansion

expansion.txt

before:

==27562== Memcheck, a memory error detector
==27562== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==27562== Using Valgrind-3.10.1 and LibVEX; rerun with -h for copyright info
==27562== Command: ./hx hx
==27562==
==27562==
==27562== HEAP SUMMARY:
==27562==     in use at exit: 0 bytes in 0 blocks
==27562==   total heap usage: 956 allocs, 956 frees, 1,638,802 bytes allocated
==27562==
==27562== All heap blocks were freed -- no leaks are possible
==27562==
==27562== For counts of detected and suppressed errors, rerun with: -v
==27562== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

after:

==28540== Memcheck, a memory error detector
==28540== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al.
==28540== Using Valgrind-3.10.1 and LibVEX; rerun with -h for copyright info
==28540== Command: ./hx hx
==28540==
==28540==
==28540== HEAP SUMMARY:
==28540==     in use at exit: 0 bytes in 0 blocks
==28540==   total heap usage: 13 allocs, 13 frees, 68,831 bytes allocated
==28540==
==28540== All heap blocks were freed -- no leaks are possible
==28540==
==28540== For counts of detected and suppressed errors, rerun with: -v
==28540== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)