Yesterday, the best answer is: abs(floor(2x)+x-abs(2x)).  (Contributed by fire. Good Job!)
turtle solved the puzzle at 03:22:12.786; length: 83
turtle solved the puzzle at 03:22:40.231; length: 79
wtfistheofficialans? solved the puzzle at 03:35:58.576; length: 78
ihavenoclue ;-; solved the puzzle at 03:36:56.605; length: 77
turtle solved the puzzle at 03:41:45.116; length: 76
turtle solved the puzzle at 03:43:34.387; length: 76
fire solved the puzzle at 16:25:45.232; length: 28
ur answer wow ;) solved the puzzle at 16:26:59.400; length: 28
try f(x)/sign(x-1) solved the puzzle at 16:28:13.379; length: 28