Teaching Kids Programming: Videos on Data Structures and Algorithms
Given a integer, we want to find out if it is divisible by 3. We can sum up the digits and check if the sum is divisble by three.
For example, 12345, the digits sum is 1+2+3+4+5 which is 15 and 15 can be divisble by 3 and thus original integer 12345 is divisble by 3.
Proof of Rule: Integer Divisible By 3
Let 
We can subtract 1 multiple from each component and add them separately, which is:
The 
def divisbleBy3(n: str):
s = 0
for i in n:
s += int(i)
return s % 3 == 0
And one-liner:
def divisbleBy3(n: str):
return sum(int(i) for i in list(n)) % 3 == 0
–EOF (The Ultimate Computing & Technology Blog) —
Last Post: Teaching Kids Programming - Topological Sort Algorithm on Directed Graphs (Course Schedule, BFS)
Next Post: Teaching Kids Programming - 0/1 Knapsack Problem via Top Down Dynamic Programming Algorithm