You are given two strings `stamp` and `target`. Initially, there is a string `s` of length `target.length` with all `s[i] == '?'`.

In one turn, you can place `stamp` over `s` and replace every letter in the `s` with the corresponding letter from `stamp`.

- For example, if `stamp = "abc"` and `target = "abcba"`, then `s` is `"?????"` initially. In one turn you can:
  - place `stamp` at index `0` of `s` to obtain `"abc??"`,
  - place `stamp` at index `1` of `s` to obtain `"?abc?"`, or
  - place `stamp` at index `2` of `s` to obtain `"??abc"`.
  Note that `stamp` must be fully contained in the boundaries of `s` in order to stamp (i.e., you cannot place `stamp` at index `3` of `s`).

We want to convert `s` to `target` using at most `10 * target.length` turns.

Return an array of the index of the left-most letter being stamped at each turn. If we cannot obtain `target` from `s` within `10 * target.length` turns, return an empty array.

Example 1:

    Input: stamp = "abc", target = "ababc"
    Output: [0,2]
    Explanation: Initially s = "?????".
    - Place stamp at index 0 to get "abc??".
    - Place stamp at index 2 to get "ababc".
    [1,0,2] would also be accepted as an answer, as well as some other answers.

Example 2:

    Input: stamp = "abca", target = "aabcaca"
    Output: [3,0,1]
    Explanation: Initially s = "???????".
    - Place stamp at index 3 to get "???abca".
    - Place stamp at index 0 to get "abcabca".
    - Place stamp at index 1 to get "aabcaca".

Constraints:

- `1 <= stamp.length <= target.length <= 1000`
- `stamp` and `target` consist of lowercase English letters.