use Vec::with_capacity avoid realloc memory

[nkysg]

TITLE

Description

Description of the pull request changes and motivation.
use Vec::with_capacity avoid realloc memory

Checklist

• Linked to Github Issue
• Unit tests added
• Integration tests added.
• This change requires new documentation.
  • Documentation has been added/updated.
  • CHANGELOG has been updated.

[pefontana]

Hi @nkysg !
Thanks for the contribution!
Do you have any benchmark to see if the PR improves the performance?

[pefontana]

Benchmark Results for unmodified programs 🚀

Command	Mean [s]	Min [s]	Max [s]	Relative
	2.522 ± 0.044	2.457	2.636	1.00
	2.563 ± 0.006	2.553	2.573	1.02 ± 0.02

Command	Mean [s]	Min [s]	Max [s]	Relative
	2.428 ± 0.037	2.394	2.508	1.00
	2.515 ± 0.022	2.497	2.564	1.04 ± 0.02

Command	Mean [s]	Min [s]	Max [s]	Relative
	9.358 ± 0.414	9.093	10.511	1.01 ± 0.05
	9.230 ± 0.087	9.158	9.472	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
	2.612 ± 0.066	2.543	2.718	1.00
	2.685 ± 0.060	2.645	2.798	1.03 ± 0.03

Command	Mean [s]	Min [s]	Max [s]	Relative
	1.703 ± 0.027	1.669	1.757	1.00
	1.780 ± 0.032	1.754	1.853	1.05 ± 0.02

Command	Mean [s]	Min [s]	Max [s]	Relative
	1.436 ± 0.012	1.418	1.457	1.00
	1.458 ± 0.013	1.442	1.486	1.02 ± 0.01

Command	Mean [s]	Min [s]	Max [s]	Relative
	9.393 ± 0.400	9.068	10.386	1.01 ± 0.04
	9.315 ± 0.082	9.246	9.520	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
	9.740 ± 0.537	9.369	10.747	1.00 ± 0.06
	9.728 ± 0.306	9.518	10.499	1.00

Command	Mean [s]	Min [s]	Max [s]	Relative
	2.563 ± 0.035	2.508	2.609	1.00
	2.644 ± 0.036	2.620	2.729	1.03 ± 0.02

Command	Mean [s]	Min [s]	Max [s]	Relative
	1.736 ± 0.027	1.706	1.799	1.00
	1.804 ± 0.008	1.794	1.822	1.04 ± 0.02

Command	Mean [s]	Min [s]	Max [s]	Relative
	1.689 ± 0.028	1.658	1.755	1.00
	1.758 ± 0.010	1.743	1.774	1.04 ± 0.02

Command	Mean [s]	Min [s]	Max [s]	Relative
	1.404 ± 0.014	1.391	1.434	1.00
	1.499 ± 0.012	1.482	1.520	1.07 ± 0.01

Command	Mean [s]	Min [s]	Max [s]	Relative
	1.817 ± 0.025	1.783	1.875	1.00
	1.871 ± 0.022	1.845	1.912	1.03 ± 0.02

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
	600.4 ± 9.2	591.0	618.6	1.00
	609.2 ± 7.3	601.2	625.1	1.01 ± 0.02

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
	700.3 ± 11.0	688.7	728.4	1.00
	718.1 ± 9.0	704.7	739.1	1.03 ± 0.02

Command	Mean [s]	Min [s]	Max [s]	Relative
	2.088 ± 0.036	2.053	2.140	1.00
	2.102 ± 0.018	2.084	2.146	1.01 ± 0.02

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
	698.8 ± 4.8	693.4	710.0	1.00
	727.1 ± 12.3	708.0	742.5	1.04 ± 0.02

Command	Mean [s]	Min [s]	Max [s]	Relative
	5.050 ± 0.054	4.981	5.112	1.00
	5.174 ± 0.062	5.123	5.338	1.02 ± 0.02

[Oppen]

If this is a bottleneck, it'd make more sense to return an array.

[Oppen]

The performance changes look more like a slight slowdown than a speedup.