O(N) set
IntuitionApproachComplexity

Time complexity:
O(N)


Space complexity:

Code
# Intuition
<!-- Describe your first thoughts on how to solve this problem. -->

# Approach
<!-- Describe your approach to solving the problem. -->

# Complexity
- Time complexity:
O(N)

- Space complexity:
<!-- Add your space complexity here, e.g. $$O(n)$$ -->

# Code
```python3 []
class Solution:
    def isFascinating(self, n: int) -> bool:
        string = str(n) + str(n*2) + str(n*3)
        s = set(['1', '2', '3', '4', '5', '6', '7', '8', '9'])
        s1 = set(string)

        return True if s1 == s and len(string) == 9 else False
```
['Python3']