The 5V input should read 3.3V ok.
The Absolute Maximum Rating of the DS1825 is 6V, so won't damage the part by connecting it to a 5V source, but it might not operate correctly or (more likely) will draw more current.
A simple resistor divider is probably sufficient. You may not be able to run the data line at maximum speed, but it should work.
If you want to get more fancy. You can use a buffer gate with open collector outputs and pull up to 3.3V in one direction and 5V in the other direction or get a level shifter, also known as a translator. These can typically operate up to many megahertz.
Good luck,
Steve T