Efficient way to remove the duplicate in an array?

Question

Input: {5, 8, 5, 3, 3, 2, 7}
Output: {5, 8, 3, 2, 7, ?, ?}

Idea is that we should remove the duplicate number from the array and should return the array in the original form (obviously without duplicate).

Please help me with an efficient algorithm or C code.

Comments

http://stackoverflow.com/questions/1532819/algorithm-efficient-way-to-remove-duplicate-integers-from-an-array

Answer 1

A good efficient hash would probably provide the best solution.

for each "element" in "input"
{
      if { not found in "hash" }
      {
             insert in "output"
             insert in "hash"
      }
}

If you know the characteristics of input array elements, then you can have much efficient solution. For example, if input array is made of characters, then your "hash" can be just 4 integer numbers on a 32-bit operating system. Each bit on the int's would represent presence/absence of the ASCII value of character. You initialize all 4 ints as all 0's and turn the bit on when you encounter a given character. So, your entire "hash" is made of 4 integers.