# Submission 063585fb...

Challenge Remove duplicate elements 0xabcdef0db461f2f... 2018-02-29 582655
``````/**
* This file is part of the 1st Solidity Gas Golfing Contest.
*
*/

pragma solidity 0.4.24;

contract Unique {
/**
* @dev Removes all but the first occurrence of each element from a list of
*      integers, preserving the order of original elements, and returns the list.
*
* The input list may be of any length.
*
* @param input The list of integers to uniquify.
* @return The input list, with any duplicate elements removed.
*/
function uniquify(uint[] input) public pure returns(uint[]) {
if (input.length < 2) {
return input;
} else if (input.length == 2) {
if (input[0] != input[1]) {
return input;
} else {
uint[] memory ret = new uint[](1);
ret[0] = input[0];
return ret;
}
} else {
return uniquify_more(input, input.length / 8);
}
}

function uniquify_more(uint[] input, uint size) internal pure returns(uint[]) {
uint[] memory filter = new uint[] (size);
uint bits = size * 256 - 1;
uint cnt = 0;
uint idx;
uint h;
uint x;
uint y;
for (idx = 0; idx < input.length; idx++) {
h = input[idx] % bits;
x = h / 256;
y = (1 << (h % 256));
if (filter[x] & y == 0) {
filter[x] = filter[x] | y;
input[cnt] = input[idx];
cnt += 1;
}
}
uint[] memory ret = new uint[](cnt);
for (idx = 0; idx < cnt; idx++) {
ret[idx] = input[idx];
}
return ret;
}
}
``````