题目 Initially on a notepad only one character A is present. You can perform two operations on this notepad for each step:
Copy All: You can copy all the characters present on the notepad (partial copy is not allowed).Paste: You can paste the characters w…
题目 Given an array of integers, 1 ≤ a[i] ≤ n (n size of array), some elements appeartwice and others appearonce.
Find all the elements that appear twice in this array.
Could you do it without extra space and in O(n) runtime?
Example:
Input:
[4,3,…