Ignoring thoughts vs. understanding them

Every day I struggle with an onslaught of negative thoughts (perfectionists with a huge ego). I came upon two different schools of thought in Buddhism teaching. One would be to try to ignore the thoughts, not give them energy, not identify with them, be present and in time they would go into the background. Basically they are just thoughts; they are not you. Another approach would be to sit down, meditate and try to go deep inside to find the root of those thoughts (I suspect I have myself deep down :P). Try to see clearly the constant river of thoughts that is happening inside (things I notice is just a small surface of things). I was never sure which one was correct.