Allocate memory for the temporary buffer when paring numbers #277

Job	Run time
macos (ENABLE_SANITIZERS, GCC)	17s
macos (ENABLE_VALGRIND, CLANG)	10s
linux (ENABLE_VALGRIND, CLANG)	33s
macos (ENABLE_SANITIZERS, CLANG)	12s
macos (NONE_MEM_CHECK, CLANG)	10s
linux (ENABLE_VALGRIND, GCC)	44s
linux (ENABLE_SANITIZERS, CLANG)	48s
macos (ENABLE_VALGRIND, GCC)	12s
macos (NONE_MEM_CHECK, GCC)	12s
linux (NONE_MEM_CHECK, CLANG)	36s
linux (NONE_MEM_CHECK, GCC)	40s
linux (ENABLE_SANITIZERS, GCC)	1m 4s
	5m 38s

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