Competitive Programming Python: Repeated sum of digits Error

Question

Don't know It's right place to ask this or not. But I was feeling completely stuck. Couldn't find better way to solve it.

I am newbie in competitive Programming. I was solving Repeated sum of digits problem Here is The Question.

Given an integer N, recursively sum digits of N until we get a single digit.

Example:-

Input:
 2
 123
 9999

Output:-
 6
 9

Here is my code:-

def sum(inp):
    if type(inp) == int:
        if len(str(inp)) <= 1:
            return inp
        else:
            a = list(str(inp))
            while len(a) > 1:
                b = 0       
                for i in a:
                    b+= int(i)
                a = list(str(b))
    return b

t = int(raw_input())
for i in range(0,t):
    print sum(i)

While submitting it gave My following error:-

Wrong !! The first test case where your code failed:

Input:
42

Its Correct output is:
6

And Your Output is:
0

However When I tested my code personally using 42 It's perfectly gives me correct Output 6.

Here is the link of question:- Repeated sum of digits Error

Answer 1

You have not implemented the code properly. You are iterating over i from 0 to t. Why?? The methodology goes as follows:

N = 12345

Calculate the sum of digits(1+2+3+4+5 = 15).

Check if it is less than 10. If so, then the current sum is the answer.. If not.. follow the same procedure by setting N = 15

Here is the code:

def sum(inp):
    while inp > 9:
        num = inp
        s = 0
        while num > 0:
            s = s + num%10
            num = num/10
        inp = s

    return inp

t = int(raw_input())
for i in range(t):
    n = int(raw_input())
    print sum(n)

Edit: I think you are iterating till t because you have considered t to be the number of testcases. So, inside the for loop, you should take another input for N for each of the testcase. [This is based on the input and output that you have provided in the question]

Edit-2: I have changed the code a bit. The question asks us to find the repeated sum of t numbers. For that, I have added a loop where we input a number n corresponding to each testcase and find its repeated sum.