Code failed 5 test cases ,plzz explain me the error

You need to follow up this logic only in your code…as per this video tutorial, Try to use the search space as mentioned in the video…

i think this problem is same as book allocation problem, am i right

Yes… It is similar to book allocation only… but you need to think for the search space in which your solution will lie…

Here we need to make search space (max_size_of_board, sum_of_all_boards) but you have created search space from (l[b-1],sum_of_all_ boards).