Given two numbers N and M. Construct maximal number by permuting (changing order) the digits of N, not exceeding M.
It is allowed to leave N as it is. If there's no Permutation of digits of N which doesn't exceed M, then print -1.
Note : Answer shouldn't have any leading zeroes.
Example 1:
Input:
N = 123
M = 222
Output:
213
Explanation: There are total 3! permutations
possible for N = 123, but the only permutation
that satisfies the given condition is 213.
Example 2:
Input:
N = 3921
M = 10000
Output:
9321
Explanation: Among all the Possible Permutations,
9321 is Maximum.
Your Task:
You don't need to read input or print anything. Your task is to complete the function maxPerm() which takes two Integers N and M as input parameters and returns the answer.
Expected Time Complexity: O(|N|^{2})
Expected Auxiliary Space: O(|N|)
Constraints:
1 ≤ A, B ≤ 10^{7}

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