Couldnt usnderstand the brute force

#1

can someone please explain this brute froce and send the brute froce code of this sum of all sub arrays question

#2
#3

this is my code it is not giving the desired result

#4

Refer this code.

#5

According to the brute force solution as mentioned in the video, 1 x 1 matrix is not included.
To include that you just have to modify the loops for bottom right coordinates. Just begin these loops from top left coordinate values.
for(int bi=li+1;bi<n;bi++){
for(int bj=lj+1;bj<n;bj++){

These must start from li and lj.