For me it was a bit the other way around. I solved the problem in a brute force way and on interviewer's asking, was flopping to come up with a better algorithm. Then he mentioned that I should consider DP.

Unfortunately my DP was really bad so I knew right then I'm going to flop. And flop I did.

For me the two weakest points are DP, and coming up with the right O() estimate for an algorithm that I just created on the whiteboard, and am looking at it for the first time in my life. Would love advice on how to get good at both.