Doubt in prefix sum matrix calculation

#1

in this video at 5:45 when he is calculating prefix sum for index(2,2] why it is not 2a+2b+c+2d+2e+f+g+h ??

#2

hi @Tanishq_Gupta
in prefix sum matrix
pre[i][j] represent sum of all elements of matrix (0,0) to (i.j)
so pre[2][2]=a+b+c+d+e+f+g+h

i hope this helps

#3

but as he is doing it should be 2a+2b+c+2d+2e+f+g+h

#4

same thing is done in video
take a look again

Screenshot from 2020-05-12 11-19-11
Screenshot from 2020-05-12 11-19-111366×768 227 KB

may be i don’t understand your doubt compeletly
if so please explain a bit more