Find duplicates in an integer array - IDeserve

Find duplicates in an integer array - IDeserve

Given an array of n elements which contains integers from 0 to n-1 only.
The numbers can appear any number of times. Find the repeating numbers.
Example:
Array:  {2, 4, 1, 2, 6, 1, 6, 3, 0}
Output: [1, 2, 6]

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