# GeetCode Hub

You are given an integer `num`. You will apply the following steps exactly two times:

• Pick a digit `x (0 <= x <= 9)`.
• Pick another digit `y (0 <= y <= 9)`. The digit `y` can be equal to `x`.
• Replace all the occurrences of `x` in the decimal representation of `num` by `y`.
• The new integer cannot have any leading zeros, also the new integer cannot be 0.

Let `a` and `b` be the results of applying the operations to `num` the first and second times, respectively.

Return the max difference between `a` and `b`.

Example 1:

```Input: num = 555
Output: 888
Explanation: The first time pick x = 5 and y = 9 and store the new integer in a.
The second time pick x = 5 and y = 1 and store the new integer in b.
We have now a = 999 and b = 111 and max difference = 888
```

Example 2:

```Input: num = 9
Output: 8
Explanation: The first time pick x = 9 and y = 9 and store the new integer in a.
The second time pick x = 9 and y = 1 and store the new integer in b.
We have now a = 9 and b = 1 and max difference = 8
```

Example 3:

```Input: num = 123456
Output: 820000
```

Example 4:

```Input: num = 10000
Output: 80000
```

Example 5:

```Input: num = 9288
Output: 8700
```

Constraints:

• `1 <= num <= 10^8`

class Solution { public int maxDiff(int num) { } }