What is the shortcut key in Ubuntu to snap one of the windows to right or left of screen with 50% width?

Install the below mentioned software.

sudo apt-get install compizconfig-settings-manager2-

open it by going to start---> settings---> compiz config settings manager -- >

then open the window management ----> grid .

there you will find the put left and put right.

and can also adjust key combination but be careful it can halt your system window manager if you make a wrong configuration there.