> The name American flag sort comes by analogy with the Dutch national flag problem[2] in the last step: efficiently partition the array into many "stripes".
[1] https://en.m.wikipedia.org/wiki/American_flag_sort
[2] https://en.m.wikipedia.org/wiki/Dutch_national_flag_problem
...or from the very article itself...
> The name American flag sort comes by analogy with the Dutch national flag problem[2] in the last step: efficiently partition the array into many "stripes".
[1] https://en.m.wikipedia.org/wiki/American_flag_sort
[2] https://en.m.wikipedia.org/wiki/Dutch_national_flag_problem