Tags: math python
Rating:
The program works as follow:
- For every number n, n and n - 1 are converted to base 3
- The program compare the digits, the number of differences is added to total
By observation, we can see that:
- For every number n, most of the time the difference is 1
- If n is divisible by 3, the difference is 2
- If n is divisible by 3, the difference is 3, and so on
Final program:
```
def count3(n):
sum = 0
while (n > 0):
sum += n
n //= 3
return sum
print(count3(523693181734689806809285195318))
```
Flag: `csictf{785539772602034710213927792950}`
