the previous blog got downvoted,so ima just make a copy

I've practiced for dp and i have found my weakness.its the dp state.somehow i never guessed it correctly.the states that i made was never relevant to the actual answer.its totally wrong.i have no clue whenever i try to make some dp states and just see if somethings correct.idk how poeple just solve dp like its 1+1.i do not know what do memoize.can someone help me?