Trying to determine residence in 2019/20

Prior employment history:

jan 2010 to april 2013 – phd student, UK
may 2013 to july 2016 – employed, UK
august 2016 to sept 2019 – employed, USA
oct 2019 to present – employed, UK

Also, I was out of the UK for the following dates in 2019/2020.

24/10/2019 to 3/11/2019 in korea for conference
21/12/2019 to 2/01/2020 in ireland for holiday
18/02/2020 to 24/02/2020 in usa for conference

Trying to determine residence in 2019/20
157 days spent in the UK from October to Mar 20 which is less than the 183 days