For the first case, for us to know the position by index shouldn't need to read the position first ?
What do you mean by reading the position? We can simple insert or delete the value without knowing whether it was there already.
For the third case i did not understand what are you saying.
What is it that you don't understand?
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What do you mean by reading the position? We can simple insert or delete the value without knowing whether it was there already.
What is it that you don't understand?