Problem 3: Veci

https://open.kattis.com/problems/veci

A couple approaches:

1. Brute Force: because the input is at most 6 digits, you only need to check numbers between the input $X$ and $999999$. You can check all numbers $i$ s.t. $X < i \leq 999999$. If any have the same digits as $X$ (can be checked by counting the # of each digit), output the smallest such $i$. Otherwise, output $0$.

2. C++ has a next_permutation() function which finds the smallest permutation larger than a given input. This function returns true if successful, and false if there are no more valid permutations. Example usage:

string s = "27711";
next_permutation(s.begin(), s.end()); // s is now 71127