ArrayHash Set
Decide whether any value appears at least twice in the array.
Input
Line 1: n. Line 2: n integers.
Output
Print true if some value appears at least twice, otherwise false.
Constraints
1 <= n <= 10^5 -10^9 <= each value <= 10^9
Example 1
Input
4 1 2 3 1
Output
true
1 appears twice.
Example 2
Input
4 1 2 3 4
Output
false
All values are distinct.