How Sir has done that?

#1

How Sir has done that? Like You can see we want to find sum[i,j]=0 but sir is doing s[i+1,j]=0, I don’t understand the logic, Please help me for that.

#2

@cbcao263
It depends on the implementation. for array[i:j] do you consider A[j] in the array or not. You need the numbers A[i],A[i+1],…,A[j].
The prefix sum array will be A[0] , A[0] + A[1] , A[0] + A[1] + A[2], … and so on.
Try to code it for a better picture and send me the code if you still do not get it.

#3

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