I don't understand the explanation part

#1

what is " " , means what i print at the last row

#2

hi @kritianu009_08c047efae64de5e that is space u need to print the pascal triangle with spaces as shown in the figure of the problem.
Pascal’s triangle is the triangular array of the binomial coefficients.The number of entries in a given line is equal to the line number.Every entry in the line is the value of a binomial coefficient. The value of ith entry in the number line is C(line,i)(i.e apply mathematical combination formula ).
Where C(line,i)=line!/((line-i)!*i!).

Given pattern can be seen as first spaces then numbers and can be formed using 3 approches:
1.A simple method is to run two loops and calculate the value of binomial coefficient in inner loop. Complexity: O(N3).
2.O(N2) time and O(n2) space complexity.In this method store the previously generated values in 2-D array. Use these values to generate value in a line.
3.O(N2) time and O(1) space complexity. In this method calculate C(line,i) using C(line,i-1). It can be calculated in O(1) time as follows:

 C(line,i-1)=line!/((line-i+1)!*(i-1)!)
 C(line,i)=line!/((line-i)!*i!)
 C(line,i)=C(line,i-1)*(line-i+1)/i.

refer this code --> https://ide.codingblocks.com/s/643422