You will be given a list of statements. You need to de-duplicate them and return a list of indices of the unique statements. Note: Two statements are considered duplicates only if they express *exactly the same thing*. If there are no duplicate statements in the list, return the complete list of indices.

You should return a List(int), where each item in the list is the index of a unique, non-duplicated statement that has been retained. For example:
[1, 3, 5]

Below is the list of statements you need to de-duplicate:
{statements}

Please begin the extraction now. Output only the integer list, without any conversational text or explanations.