I have a problem in understanding and imagining the bottom up approach in dynamic programming, for a long time I have been solving the dp problems using the memomization method and every thing was going well, but last days I faced a problems that needs an iterative approach int order to avoid the stack overflow exception, so I tried to implement the top down approach ( just like how the recursion works) and after sometime I became good in it. Now the problem is with some hard problems that I wasn't able to solve them using the top-down approach, so my friends advised me to use the bottom up one, after reading about it I was unable to imagine how it will work at all, so I read a lot of tutorials without any benefit. Can you please offer me some tutorials or videos to learn how to imagine this approach from them, because this topic made me hate the competitive programming.