Fix off by 1 error #108

Job	Run time
linux_gcc_sanitizers	2m 39s
linux_gcc_valgrind	1m 12s
linux_gcc (ubuntu-latest, Debug)	4m 34s
linux_clang (ubuntu-latest, Debug)	3m 26s
linux_gcc (ubuntu-latest, Release)	2m 30s
macos_clang (macos-latest, Debug)	5m 39s
linux_clang (ubuntu-latest, Release)	1m 9s
windows_mingw64 (windows-latest, Debug)	5m 24s
macos_clang (macos-latest, Release)	6h 0m 16s
windows_mingw64 (windows-latest, Release)	2m 46s
windows_msvc2022	2m 6s
	6h 31m 41s

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