By convention, the rows and columns of pascal's triangle are numbered starting from 0 — note that the 0th column of every row contains the value 1. to aid in the computation of edge cases (columns in rows that do not have two values above them), it is also convenient to imagine that there are columns in row 0 extending off in both directions that contain 0s. i. e., we might envision the first row of pascal's triangle as follows:
0 0 0 1 0 0 0
1 1
1 2 1
1 3 3 1
1 4 6 4 1
complete the following function, which returns the value to be found in a given row and column of pascal's triangle.