The function int [] multiply(int[] a, int [ ] b, int length) inputs two length-n arrays a and b whose elements represent the digits of two nonnegative integers that are to be multiplied (using the algorithm learned in elementary school). Here we assume that a[0 and b0] hold the least-signifanct digits of the two integers. The function then returns an array that holds the digits of a x b. For example, to multiply 54 and 145, we would pass in the arrays a -4,5,0 and b- 5,4,1, and the function should return the array 0,3,8,7. Implement this function using "Java" or "C"-like pseudocode. Then provide an appropriate summation expression that models its running time T(n). Simplify the summation expression to an expression in terms of n, and use it to determine either a big-O or big- representation of running time T(n). Hint: first implement a function that multiplies a nonnegative integer by a single digit, then call this function, along with the add function within a loop to complete the entire multiplication