Question: 
Write a python function to find sum of products of all possible subarrays.


Model's Code:
def sum_Of_Subarray_Prod(arr, n):
    total_sum = 0
    for i in range(n):
        product = 1
        for j in range(i, n):
            product *= arr[j]
            total_sum += product
    return total_sum



Sample Correct Code:
def sum_Of_Subarray_Prod(arr,n):
    ans = 0
    res = 0
    i = n - 1
    while (i >= 0):
        incr = arr[i]*(1 + res)
        ans += incr
        res = incr
        i -= 1
    return (ans)


Asserts:
assert sum_Of_Subarray_Prod([1,2,3],3) == 20
assert sum_Of_Subarray_Prod([1,2],2) == 5
assert sum_Of_Subarray_Prod([1,2,3,4],4) == 84


Tests:
Test 1 of 3: PASS
Test 2 of 3: PASS
Test 3 of 3: PASS

Test 734 of 974: 556/734 (75.74931880108991%): success