Android - Skip ads from YouTube
You're interested in the Youtube AdAway Xposed Module. It requires root access and the Xposed Framework.
It completely removes the following:
- YouTube ads
- channel logos
- video suggestions
- information card teasers
To the best of my knowledge, what you've requested (auto skipping advertisements in the stock Youtube application) cannot be done without root access. Root access is required to 1) draw over other apps and 2) record/replay touches.
See:
- Bot Maker for Android
- RepiTouch Free
- HiroMacro Auto-Touch Macro
As @Six stated very correctly, it is NOT possible to do without root access at all. His answer is pretty good but there is still some things I can add.
A non-rooted phone quite literally means a phone that can only be used the way manufacturer wants it to be. Its power is limited to how much the manufacturer wants you to have (and for good reason according to some people, which sometimes includes me too)
On a non-rooted phone, no third party app can emulate screen touches, modify the loaded or running copies of other apps or access to data of other apps. All for security reasons.
So your wish can't be granted without root access.