Why the touch screen is not working?

@adityajosh99614 "Since the phone is been to water" means that you have a water damaged phone. That in turn means you will need to deal with the water damage first.

For now, stop continuing to try to charge, sync or otherwise use your phone. This potentially can make a bad situation worse. This may further damage your phone.

The next thing to do is to clean it. Since iFixit does not yet have a specific guide for this, use this Samsung GT C3300K Disassembly. to work on it. Remove the main board and the charging board. You will have to remove the EMI shields from the main board. If you do not remove the shield, you are not cleaning the board.

Take a close look at all components and connectors to assess the damage. Look for major corrosion, evaluate the pins in the connectors etc. Pay particular attention to the touchscreen connector (called the TSP connector in the manual) Take a look at all connectors as well as cable ends. For a proper cleaning, use this guide. It was written for an Apple iPhone 3G but all the steps are still pertinent to your phone as well. I can not stress the importance of a good cleaning enough, so do it over and over while replacing the alcohol after each cleaning. While you clean your board, check for any obvious damage, like burned or missing components etc. The importance here is the cleaning.

When it is properly cleaned, replace the battery. This is a must and not an option. It will fail if you do not take care of it now. All these steps are to avoid delayed failure caused by corrosion. Best thing to do would be to clean it with an ultrasonic cleaner, but if you do not have access to one, this will at least help. Once all this is done, reassemble your phone and reevaluate. Until it is cleaned, everything will only be a guess. It is possible that you have a bad touchscreen and you may need to replace it to get full function back to your phone. Finding a replacement will require some detective work since those are not readily available. Do a good internet search or consider getting a "donor phone" from places like eBay etc. and harvest the touchscreen from that.