CF1560F2.Nearest Beautiful Number (hard version)

It is a complicated version of problem F1. The difference between them is the constraints (F1: $k \le 2$ , F2: $k \le 10$ ).

You are given an integer $n$ . Find the minimum integer $x$ such that $x \ge n$ and the number $x$ is $k$ -beautiful.

A number is called $k$ -beautiful if its decimal representation having no leading zeroes contains no more than $k$ different digits. E.g. if $k = 2$ , the numbers $3434443$ , $55550$ , $777$ and $21$ are $k$ -beautiful whereas the numbers $120$ , $445435$ and $998244353$ are not.

The first line contains one integer $t$ ( $1 \le t \le 10^4$ ) — the number of test cases. Then $t$ test cases follow.

Each test case consists of one line containing two integers $n$ and $k$ ( $1 \le n \le 10^9$ , $1 \le k \le 10$ ).

For each test case output on a separate line $x$ — the minimum $k$ -beautiful integer such that $x \ge n$ .