Problem
Look at every decimal digit of n and return the largest one.
Implement largest_digit(n).
Input
n: A positive integer.
Output
Return the largest digit, from 0 to 9.
Constraints
1 ≤ n ≤ 10¹⁸
Examples
Example 1
Input:
n = 352
Expected output:
expected = 5Input:
long long n = 352;
Expected output:
long long expected = 5;Input:
long n = 352;
Expected output:
long expected = 5;Explanation
The digits are 3, 5 and 2; the largest is 5.
Example 2
Input:
n = 7
Expected output:
expected = 7Input:
long long n = 7;
Expected output:
long long expected = 7;Input:
long n = 7;
Expected output:
long expected = 7;Explanation
The only digit is 7.