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.
stamp = "abc" and target = "abcba", then s is "?????" initially. In one turn you can:
<ul>
<li>place <code>stamp</code> at index <code>0</code> of <code>s</code> to obtain <code>"abc??"</code>,</li>
<li>place <code>stamp</code> at index <code>1</code> of <code>s</code> to obtain <code>"?abc?"</code>, or</li>
<li>place <code>stamp</code> at index <code>2</code> of <code>s</code> to obtain <code>"??abc"</code>.</li>
</ul>
Note that <code>stamp</code> must be fully contained in the boundaries of <code>s</code> in order to stamp (i.e., you cannot place <code>stamp</code> at index <code>3</code> of <code>s</code>).</li>
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 <= 1000stamp and target consist of lowercase English letters.